Сводная информация о патентах США
(тематическая подборка "clutter")
| N п/п | Номер патента | Название | Реферат | Автор(ы) | Заявитель(ли) | Приоритет | Дата выдачи | МПК | Номер заявки |
| 1 | 8358239 | Iterative clutter calibration with phased array antennas | An iterative clutter calibration method comprises measuring an average of a sidelobe power in a range-Doppler image for a plurality of ranges. A determined value of an objective function is responsive to an average of the sidelobe clutter power. A plurality of beamformer weights is modified and the step of determining the value of the objective function is repeated until a maximum value of the objective function is determined. Each beamformer weight determines a gain and phase of a respective antenna element in an antenna system | Krich Steven Ira (Lexington, MA), Weiner Ian (Braintree, MA), Krich Steven Ira | Massachusetts Institute of Technology (Cambridge, MA) | 24.03.2011 | 22.01.2013 | G01S7/40 | 13/070566 |
| 2 | 8342027 | Determining physical properties of objects or fluids in multi-path clutter environments | A method for determining a physical property of an object or fluid in a dynamic multi-path clutter environment comprises transmitting an RF interrogation signal to a wireless sensor physically coupled to the object or fluid (gas or liquid) in the dynamic multi-path clutter environment, wherein the wireless sensor is operable to receive the RF interrogation signal, produce a reference signal and a measurement signal, and retransmit the reference signal and the measurement signal in the dynamic multi-path clutter environment. The reference signal and measurement signal are delayed by the wireless sensor by an amount of time that may be a function of the unknown physical property. The method also comprises receiving the retransmitted reference signal and the retransmitted measurement signal and comparing them in the time domain in The method further comprises setting the time delays of the retransmitted reference and retransmitted measurement signals to be long enough for the ringdown time to be over but not so long so that the differential time is distorted by the dynamics of the system | Walton Eric K. (Columbus, OH), Bayram Yakup (Dublin, OH), Tuncay Orbay (Emmaus, PA), Montgomery Bruce G. (Glenwood, MD), Bruce Gary W. (Severna Park, MD), Crowe Douglas E. (Herdon, VA), Gemeny Steven E. (Finksburg, MD) | The Ohio State University (Columbus, OH), Syntonics, LLC (Columbia, MD) | 03.08.2011 | 01.01.2013 | G01N29/36, G01N29/022, G01N29/2481, G01N29/30, G01N29/4436, G01N29/4481, G01N2291/0423 | 13/197465 |
| 3 | 8313435 | Clutter signal filtering in an ultrasound system | Examples for filtering clutter signals from receive signals obtained in a Doppler mode in an ultrasound system are disclosed. The signal processing unit processes received echoes to provide 2-dimensional image data of the target object, the 2-dimensional image data being representative of a 2-dimensional image. A region of interest (ROI) is set on the 2-dimensional image of the target object, The signal processing unit obtains a Doppler mode image pixel data corresponding to the ROI. The signal processing unit sets filter cutoff frequencies based on characteristics of the Doppler mode image pixel data and filter the Doppler mode image pixel data with the set filter cutoff frequencies to output filtered pixel data with clutter signals filtered | Kim Tae Yun (Seoul, KR) | Medison Co., Ltd. (Kangwon-do, KR) | 13.03.2009 | 20.11.2012 | A61B8/00, G01S7/5205, G01S15/8981, G01S7/52063 | 12/404248 |
| 4 | 8306296 | Clutter signal filtering using eigenvectors in an ultrasound system | Embodiments for setting eigenvectors for clutter signal filtering from Doppler signals in an ultrasound system are disclosed. In one embodiment, the ultrasound system includes:a Doppler signal acquisition unit configured to transmit and receive ultrasound signals to and from a target object to acquire first Doppler signals: and a processing unit configured to compute a plurality of eigenvectors by using the first Doppler signals and form second Doppler signals corresponding to directions of the computed eigenvectors, the processing unit being further configured to compute component values of the second Doppler signals and set eigenvectors for clutter signal filtering among the plurality of eigenvectors by using the computed component values | Song Seong Ho (Suwon-si, KR), Kim Tae Yun (Seoul, KR) | Medison Co., Ltd. (Kangwon-do, KR) | 28.04.2010 | 06.11.2012 | G06K9/00, A61B8/00, A61B8/488, G01S15/8981 | 12/769411 |
| 5 | 8305261 | Adaptive mainlobe clutter method for range-Doppler maps | A method of adaptively removing mainlobe clutter from range-Doppler data includes estimating the peak of the mainlobe clutter, and determining clutter regionboundaries adaptively and robustly. The mainlobe clutter peak may be estimated from the range-Doppler data, for example using both nonlinear and linear filters. Alternatively the mainlobe clutter peak may be estimated from knowledge of the position and speed of the vehicle, such as a missile, upon which the radar system moves. The clutter boundaries may be determined at each of the range bins by stepping along Doppler bins from the mainlobe clutter peak estimate in opposite directions, locating the boundary at locations off of the mainlobe clutter peak estimate that meet a given criterion. The method produces a finer determination of the mainlobe clutter region, resulting in less of the range-Doppler data being excluded as part of the mainlobe clutter region | Hunter Kyle P. (Tucson, AZ) | Raytheon Company (Waltham, MA) | 02.04.2010 | 06.11.2012 | G01S13/50, G01S13/5242, G01S13/5244 | 12/753335 |
| 6 | 8237606 | UHF radar system for implementing a method of eliminating vegetation clutter | A system includes a pulsed UHF radar for integrating the signal received over a given integration time. The integration time for the received signal and the size of the distance bin are defined in such a way that, taking into account the range of speeds of the targets of interest, a moving target of interest travels only a distance shorter than the size of the distance bin from one integration period to another. Furthermore, the UHF radar implements a method of forming radar blips from the received signal to form elementary blips from the signals received over the chosen integration time and to store them from one burst to another. The method also confirms that the elementary blips formed probably correspond to targets of interest and then forms, from the confirmed elementary blips, aggregate blips, the attributes of an aggregate blip depending on the attributes of the confirmed elementary blips from which the aggregate blip stems. The method also validates the aggregate blips formed, the validation of an aggregate blip depending on the distance measurement associated with this blip. The transmission of parasitic blips is reduced, brought about by the detection of echos relating to the movement of vegetation due to the action of the wind, to the tracking means | Molin Paul (Paris, FR), Ricci Yves (Courbevoie, FR) | Thales Deutschland GmbH (Stuttgart, DE) | 10.12.2010 | 07.08.2012 | G01S13/62, G01S7/2923, G01S13/581, G08B13/1627, G08B29/18 | 12/965721 |
| 7 | 8214440 | Controlling the display of sensitive information and managing visual clutter in a live session display area system | A system for clearing content displayed in the live session display area of an instant messaging system. The system enables a session participant to clear the content currently visible to each other participant in the session, either immediately, or in response to a criteria such as elapsed time or elapsed time since active in the session. The content that is cleared from the live session display area is not permanently lost, but is only temporarily hidden from the live session display area. The system further enables a local participant to recall such temporarily hidden content back into the live session display area | Lyle Ruthie D. (Durham, NC), Jones Doris L. (Somerville, MA), Ryan Corinne M. (Westford, MA) | International Business Machines Corporation (Armonk, NY) | 10.04.2007 | 03.07.2012 | G06F15/16 | 11/733670 |
| 8 | 8189427 | Clutter signal filtering for doppler signal | Embodiments for filtering clutter signal from Doppler signal in an ultrasound system are disclosed. In one embodiment, a Doppler signal acquiring unit may transmit and receive ultrasound signals to and from a target object to acquire Doppler signal. A signal processing unit performs filtering upon the Doppler signal by using a first clutter filter having a first cutoff frequency and compute an input signal power to filtered input signal power rate (IFR) for the Doppler signal. The signal processing unit is further configured to be responsive to the IFR to modulate the Doppler signal and perform filtering upon the modulated Doppler signal by using the first clutter filter or to perform filtering the Doppler signal by using a second clutter filter having a second cutoff frequency | Lee Kwang Ju (Seoul, KR), Kim Jong Sik (Seoul, KR) | Medison Co., Ltd. (Kangwon-Do, KR) | 14.12.2009 | 29.05.2012 | G01S15/00, G03B42/06, G01S15/8981 | 12/637652 |
| 9 | 8179300 | Method for suppressing clutter in space-time adaptive processing systems | A method surpresses clutter in a space-time adaptive processing system. The method achieves low-complexity computation via two steps. First, the method utilizes an improved fast approximated power iteration method to compress the data into a much smaller subspace. To further reduce the computational complexity, a progressive singular value decomposition (SVD) approach is employed to update the inverse of the covariance matrix of the compressed data. As a result, the proposed low-complexity STAP computational complexity reduction as compared to the conventional STAP procedure | Pun Man-On (Cambridge, MA), Sahinoglu Zafer (Arlington, MA) | Mitsubishi Electric Research Laboratories, Inc. (Cambridge, MA) | 29.01.2010 | 15.05.2012 | G01S13/00 | 12/696997 |
| 10 | 8174435 | Methods and apparatus for non-isotropic sea clutter modeling | Methods and apparatus to provide computing, using a processor, sea clutter threshold bias values as a function of range and azimuth, receiving a first shape corresponding to a first region of sea clutter about a radar, combining the sea clutter threshold bias values with the first shape to provide non-isotropic sensitivity time control (STC) for the radar, and outputting radar return for display with sea clutter suppressed in the first shape | Habboosh Amir W. (Somerset, MA), Willis Nicholas F. (E. Greenwich, RI), Wood Thomas E. (Portsmouth, RI) | Raytheon Company (Waltham, MA) | 01.06.2010 | 08.05.2012 | G01S13/00, G01S7/34, G01S13/10 | 12/791038 |
| 11 | 8159388 | Method for filtering sea clutter in a radar echo using a hydrographic model | There is disclosed a method for filtering sea clutter in a radar echo using a hydrographic model. The method comprises the steps of determining parameter values of the hydrographic model using the radar echo, estimating the sea clutter corresponding to the sea surface as deduced from the hydrographic model and filtering of the estimated sea clutter from the radar echo | Erkocevic-Pribic Radmila (Delgauw, NL), Karelse Jan (Delft, NL), Langeraar Hubert (Hengelo, NL) | Thales Nederland B.V. (Hengelo, NL) | 26.04.2007 | 17.04.2012 | G01S13/00, G01S7/2923, G01S7/414 | 12/299497 |
| 12 | 8144050 | Removing clutter from radar cross section measurements using spectral tagging | A system for performing radar cross section measurements of a target may include a radar system and an antenna associated with the radar system to transmit signals and to receive reflected signals from the target and a clutter source. An EM tagging device is locatable proximate to the clutter source to spectrally tag the clutter source by causing changes in an electromagnetic signal reflected by the clutter source when a predetermined radar signal transmitted by the radar system is incident on the target, the clutter source and the EM tagging device. A module may identify a spectrally tagged component of reflected signals received by the radar system from the target, the clutter source and the EM tagging device. The module monitors the spectrally tagged component, compensates for variations in an un-tagged component of the reflected signals caused by the clutter source and EM tagging device, and subtracts contamination caused by the clutter source and EM tagging device and their interactions with the target, to provide a radar cross section of the target with reflected signals from the clutter source removed | Foster John D. (East Tacoma, WA), Morgan Douglas P. (Auburn, WA), McLean Scot J. (Renton, WA) | The Boeing Company (Chicago, IL) | 25.02.2011 | 27.03.2012 | G01S7/41, G01S7/411, G01S13/753, H01Q3/01, H01Q7/00 | 13/034852 |
| 13 | 8098196 | Time-compressed clutter covariance signal processor | The time compression processor coding methodology gives rise to an exceedingly fast clutter covariance processor compressor (CCPC). The CCPC includes a look up memory containing a very small number of predicted clutter covariances (PCCs) that are suitably designed off-line (e.g., in advance) using a discrete number of clutter to noise ratios (CNRs) and shifted antenna patterns (SAPs), where the SAPs are mathematical computational artifices not physically implemented. The on-line selection of the best PCC is achieved by investigating for each case, e.g., each range bin, the actual CNR, as well as the clutter cell centroid (CCC), which conveys information about the best SAP to select. The advanced CCPC is a `lossy` processor coder that inherently arises from a novel practical and theoretical foundation for signal processing, namely, processor coding, that is the time compression signal processing dual of space compression source coding | Feria Erlan H. (Princeton, NJ) | Research Foundation of the City University of New York (New York, NY) | 11.04.2007 | 17.01.2012 | G01S13/00, G01S7/295, G01S13/5242, G01S13/9029 | 12/296908 |
| 14 | 8045777 | Clutter suppression in ultrasonic imaging systems | A method for ultrasonic imaging includes transmitting ultrasonic radiation toward a target and receiving the ultrasonic radiation reflected from a region of the target. A main reflected signal and an auxiliary reflected signal are defined. The reflected signals have different respective main and auxiliary beam patterns. A difference between the main reflected signal and the auxiliary reflected signal is taken, so as to generate an output signal containing a reduced level of clutter in comparison with the main reflected signal | Zwirn Gil (Petach Tikva, IL) | Crystalview Medical Imaging Limited (St. Helier, Jersey, Channel Islands, GB) | 27.12.2005 | 25.10.2011 | G06K9/00, G01S7/52026, G01S7/52046, G01S15/8993, A61B8/14, G01S7/52077 | 11/722246 |
| 15 | 7990311 | Adaptive clutter filter for maritime surface search radar | A time sequence of raw radar data for a region of space is subdivided into a plurality of processing frames. The processing frames are subdivided into a plurality of processing cells and iteratively processed by selecting a single processing cell for processing, transforming the radar data of the processing cell to form transformed radar data in either the time domain or the Fourier domain. The transformed data is converted to a Power Spectrum Density Matrix in the case of the Fourier domain and a Time Space Correlation Matrix in the case of the time domain. This is smoothed and thresholded and then the clutter for the processing cell is estimated. Estimated local non-speckle clutter is estimated and removed from the transformed radar data, with the cleaned transformed radar data converted back to the time domain if required | Pauli Mark D. (West Hills, CA), Blind Jason (Huntington Beach, CA) | Raytheon Applied Signal Technology, Inc. (Sunnyvale, CA) | 30.10.2009 | 02.08.2011 | G01S7/292, G01S7/2927, G01S7/414, G01S13/9307 | 12/610252 |
| 16 | 7969349 | System and method for suppressing close clutter in a radar system | A system for processing electromagnetic waves in a radar system is disclosed. The system includes a transmitter operable to transmit operating waves and calibration waves, one or more receivers operable to receive reflected calibration waves and operating waves, and a system controller operable to process the received calibration waves and operating waves. The system controller may process the received waves by generating a threshold signal based on the calibration waves, and comparing the threshold signal to the operating waves. The system controller may also process operating waves and calibration waves in accordance with one or more signal conditioning algorithms. Additionally, the system controller may display an image representing a target on a display by comparing received operating waves with the generated threshold signal | Holzheimer Timothy R. (Rockwall, TX), Goodman Vernon R. (Rockwall, TX) | Raytheon Company (Waltham, MA) | 06.04.2009 | 28.06.2011 | G01S13/00, G01S7/40, G01S7/414, G01S13/931 | 12/418958 |
| 17 | 7965384 | Clutter rejection in active object detection systems | According to a method and apparatus taught herein an active object detection system performs reliable object detection based on light pulse emissions and corresponding and time-of-flight based distance determination, while advantageously rejecting clutter. While not limiting, the method and apparatus taught herein may be particularly advantageous for safety-critical object detection applications, such as where the active object detection system, e.g., a laser scanner, monitors for objects of at least a specified size within a predetermined monitoring radius or contour | Drinkard John (Foster City, CA) | Omron Scientific Technologies, Inc. (Fremont, CA) | 24.09.2008 | 21.06.2011 | G01C3/08, G01S7/4812, G01S7/4813, G01S7/4817, G01S7/487, G01S17/42 | 12/237065 |
| 18 | 7916067 | Removing clutter from radar cross section measurements using spectral tagging | A system for performing radar cross section measurements of a target may include a radar system and an antenna associated with the radar system to transmit signals and to receive reflected signals from the target and a clutter source. An EM tagging device is locatable proximate to the clutter source to spectrally tag the clutter source by causing changes in an electromagnetic signal reflected by the clutter source when a predetermined radar signal transmitted by the radar system is incident on the target, the clutter source and the EM tagging device. A module may identify a spectrally tagged component of reflected signals received by the radar system from the target, the clutter source and the EM tagging device. The module monitors the spectrally tagged component, compensates for variations in an un-tagged component of the reflected signals caused by the clutter source and EM tagging device, and subtracts contamination caused by the clutter source and EM tagging device and their interactions with the target, to provide a radar cross section of the target with reflected signals from the clutter source removed | Foster John D. (East Tacoma, WA), Morgan Douglas P. (Auburn, WA), McLean Scot J. (Renton, WA) | The Boeing Company (Chicago, IL) | 11.02.2009 | 29.03.2011 | G01S7/41, G01S7/411, G01S13/753, H01Q3/01, H01Q7/00 | 12/369273 |
| 19 | 7903024 | Adaptive moving target indicator (MTI) clutter rejection filter for radar systems | Apparatus for providing moving target indicator (MTI) filtering in the presence of clutter for a radar receiver employing digital pulse compression to provide at an output a compressed digital pulse for application to the input of a MTI digital filter, including a digital adaptive filter of the same weight as the MTI filter and operative to receive the compressed pulse to provide at outputs of the filter a set of weighted filter coefficients, wherein the weighted coefficients are applied to the MTI filter during a predetermined clutter mode | Tietjen Byron W. (Baldwinsville, NY), Au Melinda M. (Grand Prairie, TX), Freeman Kevin P. (Liverpool, NY) | Lockheed Martin Corporation (Bethesda, MD) | 25.10.2007 | 08.03.2011 | G01S13/52, G01S13/28, G01S13/5244, G01S13/5246 | 11/977639 |
| 20 | 7852259 | Clutter filtering | Clutter filtering of broadband radar signals is performed by obtaining a measure of the impedance of an echo target. A distance resolution is selected and then a power spectrum is calculated for the necessary transmitting signal. Further a target area profile .rho.(.tau.) is estimated by utilising a correlation between the radiated signal and the received signal in form of a convolution. The target impedance is then calculated, and thereafter, the target can be filtered out using the achieved impedance characterising the echo of the target | Falk Kent Olof (Go{umlaut over ( )}teborg, SE) | Telefonaktiebolaget LM Ericsson (publ), (Stockholm, SE) | 17.07.2006 | 14.12.2010 | G01S13/00, G01S7/414, H01Q21/08, H01Q21/205, H01Q21/28 | 11/487585 |
| 21 | 7831063 | Small event detector in presence of clutter | A system and method for displaying a plurality of images. In one embodiment, the system includes:(1) an event detector configured to detect at least one true target in the plurality of images using a threshold based on average and peak pixel values, (2) an image processor configured to define at least one corresponding region-of-interest for the at least one true target, (3) at least one display configured to display the plurality of images on at least one display and (4) a region-of-interest display separate from the at least one display and configured to display the at least one region-of-interest | Laughlin Richard H. (Grapevine, TX), Family ID | --- | 19.02.2007 | 09.11.2010 | G06K9/00, G06T7/2053, G08B13/19682, H04N7/18 | 11/676380 |
| 22 | 7830299 | Radar system for manmade device detection and discrimination from clutter | A radar system for detecting the presence of threat providing electronic manmade devices placed in a given area of operation comprising:a radar transmitter for transmitting a radar signal designated as a probe signal to the given area of operation to cause said threat providing devices to produce anomalous energy signals, a radar receiver for receiving a reflected radar signal from said area of operation including said anomalous energy signals, designated as Target Anomalous Response (TAR) signals, a circuit responsive to the received signal for processing the signal to detect the (TAR) anomalous energy signals indicative of a threat producing device | Steele Daniel W. (Clay, NY), Rotondo Frank S. (Manlius, NY), Houck Jeffrey L. (Tully, NY) | Lockheed Martin Corporation (Bethesda, MD) | 28.11.2007 | 09.11.2010 | G01S7/42, G01S13/00, G01S7/414, G01S13/887, G01S13/5242 | 11/998179 |
| 23 | 7796082 | Methods and apparatus for log-FTC radar receivers having enhanced sea clutter model | Methods and apparatus to provide Log-Amp-detected radar sea clutter voltage modeled by a polynomial, such as a cubic polynomial, and using that model as a basis for sea clutter reduction filtering. In an exemplary embodiment, a navigational radar includes an STC filter design based on the cubic sea clutter modeling | Wood Thomas E. (Portsmouth, RI) | Raytheon Company (Waltham, MA) | 08.02.2007 | 14.09.2010 | G01S7/292, G01S7/285, G01S13/00, G01S7/02, G01S7/34, G01S7/414, G01S13/9307, G01S13/956 | 11/672813 |
| 24 | 7773029 | System and method for filtering clutter | A system and method for filtering clutter is contemplated that in one aspect performs clutter-filtering on complex-voltages. In one aspect, spectral coefficients identified from a series of spectral coefficients as having been affected by clutter are replaced by a refilling procedure to maintain the statistical properties of the spectral coefficients that are unaffected by clutter. Dual-polarization radar variables that have phase dependence can be subsequently generated from the modified spectral data | Bachman Svetlana M (Liverpool, NY) | Lockheed Martin Corporation (Bethesda, MD) | 10.03.2009 | 10.08.2010 | G01S13/53, G01S13/95, G01S7/025, G01S13/53, G01S13/953 | 12/401391 |
| 25 | 7742640 | Reduction of background clutter in structured lighting systems | Methods for segmenting the reflected light of an illumination source having a characteristic wavelength from background illumination (i.e. clutter) in structured lighting systems can comprise pulsing the light source used to illuminate a scene, pulsing the light source synchronously with the opening of a shutter in an imaging device, estimating the contribution of background clutter by interpolation of images of the scene collected at multiple spectral bands not including the characteristic wavelength and subtracting the estimated background contribution from an image of the scene comprising the wavelength of the light source and, placing a polarizing filter between the imaging device and the scene, where the illumination source can be polarized in the same orientation as the polarizing filter. Apparatus for segmenting the light of an illumination source from background illumination can comprise an illuminator, an image receiver for receiving images of multiple spectral bands, a processor for calculations and interpolations, and a polarizing filter | Carlson Jeffrey J. (Albuquerque, NM), Giles Michael K. (Las Cruces, NM), Padilla Denise D. (Albuquerque, NM), Davidson, Jr. Patrick A. (Albuquerque, NM), Novick David K. (Albuquerque, NM), Wilson Christopher W. (Albuquerque, NM) | Sandia Corporation (Albuquerque, NM) | 13.10.2006 | 22.06.2010 | G06K9/34, G06K9/2018, G06K9/2036, G06T7/0057, G06T7/0081, G06T7/0097, G06T2207/20144, G06T2207/20224 | 11/580572 |
| 26 | 7728769 | Adaptive processing method of clutter rejection in a phased array beam pattern | An adaptive processing method of and system for clutter rejection in a phased array beam pattern. The amplitude distribution of the transmit elements of a two-dimensional phased array is determined. A desired pattern with low side lobes for a linear array is synthesized. The amplitude distribution of the transmit elements of the two-dimensional phased array is compared with the synthesized pattern. Select elements of the two-dimensional array are disabled to best fit the determined amplitude distribution of the transmit elements of the two-dimensional phased array to the synthesized beam pattern. Phase only pattern synthesis is performed to produce a desired two-dimensional beam pattern with low side lobes to minimize any best fit errors | Chang Kaichiang (Northborough, MA), Kennedy William (Boston, MA) | Raytheon Company (Waltham, MA) | 12.03.2008 | 01.06.2010 | H01Q3/26, G01S7/414, H01Q3/2605, H01Q21/22, G01S2013/0254 | 12/075510 |
| 27 | 7728765 | Method and apparatus for clutter filtering staggered pulse repetition time signals | A method for clutter filtering staggered pulse repetition time data signals is provided. The method comprises the steps of receiving a plurality of staggered pulse repetition time data signals. The data signals may comprise one or more desired signals and one or more clutter signals. The method further comprises separating the staggered pulse repetition time data signals into a first separated data sequence and a second separated data sequence. The first and second separated data sequences comprise equally spaced data samples. The method also comprises the step of filtering the one or more clutter signals from the first and second separated data sequences | Gray Grant (Marble Canyon, AZ), Hubbert John (Fort Collins, CO), Meymaris Gregory (Boulder, CO) | University Corporation of Atmospheric Research (Boulder, CO) | 07.05.2009 | 01.06.2010 | G01S7/292, G01S13/22, G01S13/00, G01S7/02, G01S7/2923, G01S13/225, G01S13/95 | 12/436945 |
| 28 | 7681129 | Audio clutter reduction and content identification for web-based screen-readers | A method and apparatus for reading a web page according to a set of user-configurable settings. In one embodiment, a set of user-configurable settings configured for reading the web page is determined. An initial reading position on the web page is determined as specified by the user-configurable settings. The web page is then read from the initial reading position according to the set of user-configurable settings | Cragun Brian John (Rochester, MN) | International Business Machines Corporation (Armonk, NY) | 04.04.2006 | 16.03.2010 | G06F17/00, G10L13/08 | 11/397407 |
| 29 | 7652614 | Ground clutter mitigation using a parametric time domain method | Methods and systems are disclosed for investigating a region of interest with a radar. A radar signal is propagated to the region of interest. Sampled time-domain radar data scattered within the region of interest are collected. A likelihood function is calculated with the sampled time-domain data within a parametric model of the region of interest for a defined set of parameters. The set of parameters in varied to find an extremum of the likelihood function | Venkatachalam Chandrasekaran (Fort Collins, CO), Moiseev Dmitriy (Fort Collins, CO), Nguyen Cuong (Fort Collins, CO) | Colorado State University Research Foundation (Fort Collins, CO) | 30.07.2007 | 26.01.2010 | G01S13/95, G01S7/292, G01S13/227, G01S13/5244, G01S13/951 | 11/830574 |
| 30 | 7570202 | Polarimetric selectivity method for suppressing cross-track clutter in sounding radars | Methods for suppressing cross-track clutter in a sounding radar utilize polarimetric selectivity in two ways:(1) transmitting full-beam circular polarization and separating the desired signal of interest from the clutter based on the signal and clutter having different polarizations, and (2) transmitting and receiving circular polarization at the radar's nadir and elliptical polarization at the radar's off-nadir regions and filtering out the elliptical polarization | Raney Russell K. (Annapolis, MD) | The Johns Hopkins University (Baltimore, MD) | 16.05.2008 | 04.08.2009 | G01S13/89, G01S7/026, G01S2013/9076 | 12/121841 |
| 31 | 7548187 | Adaptive clutter filtering to improve high sub-clutter visibility radar detection performance | In an aircraft-mounted Doppler radar clutter rejection system, a flexible, sharp band pass filter uses Taylor weighting, an FFT and a module for selecting which of the Doppler cells are to be activated, thus to control the band pass characteristic and set the clutter line to the speed of the aircraft | Laste Gregory S. (Hudson, NH), Murdza Garret E. (Nashua, NH) | BAE Systems Information and Electronic Systems Integration Inc. (Nashua, NH) | 08.11.2006 | 16.06.2009 | G01S13/00, G01S13/50, G01S13/5244 | 11/594419 |
| 32 | 7538717 | Adaptive ground clutter cancellation | The present invention refers to an airborne radar device (1) comprising at least two antennas (2, 3) and clutter suppressing means (4). The radar device is arranged, via the antennas (2, 3) to send out radar pulses focused in main lobes (5) and the antennas are arranged to receive reflecting pulses. The antennas (2, 3) are separated from each other vertically. The radar device (1) comprises means (6) for transforming the received radar pulses into complex video signals in the form sequences of range bins (R.sub.k). The video signals are represented in a first channel (K.sub.1) and a second channel (K.sub.2) | Erikmats Osten (Molnlycke, SE), Rizell Svenolov (Gr{dot over (a)}bo, SE), Kindberg Per-Arne (M{dot over (o)}lnlycke, SE), Andersson Ake (M{dot over (o)}lndal, SE) | SAAB AB (Linkoping, SE) | 20.12.2002 | 26.05.2009 | G01S13/52, G01S7/28, G01S7/292, G01S13/00, G01S13/5242, G01S7/2813, G01S13/449 | 10/538044 |
| 33 | 7525102 | Agent detection in the presence of background clutter | The present invention generally provides systems and methods for detection of agents of interest in a bulk quantity of matter, which also contains clutter and other constituents that typically interfere with the detection of one or more agents of interest. A detection system of the invention generally contains a collection subsystem for obtaining a bulk sample, an interrogation subsystem for generating one or more analytical signals representative of the composition of the bulk sample, and an analytical subsystem according to the teachings of the invention that implements the methods and algorithms of the invention for analyzing the sample analytical signals to determine whether one or more agents of interest are present, e.g., at quantities above a certain threshold, in the bulk sample | Henshaw Philip D. (Carlisle, MA), Trepagnier Pierre C. (Medford, MA) | Sparta, Inc. (Billerica, MA) | 02.10.2006 | 28.04.2009 | G01J3/28, G01J3/28, G01J3/44, G01N21/6408, G01N2021/6417, G01N2021/6421, G01N2201/129 | 11/541935 |
| 34 | 7483800 | Peak detection and clutter reduction for a microwave sensor | An effective methodology for reducing the influence of clutter arising from a complex signal environment defined by the use of a microwave sensor within or in connection with a gas turbine engine having one or more stages of rotating blades. Accurate detection of peak signals for blade measurements can be obtained by the microwave sensor | Geisheimer Jonathan (Neyruz, CH), Holst Thomas (Villars-sur-Glane, CH) | Radatec, Inc. (Londonderry, NH) | 01.06.2007 | 27.01.2009 | G01R23/16, F01D21/003, G01S7/415, G01S13/505, G01S13/88, F05B2250/20 | 11/809499 |
| 35 | 7460059 | Removing interfering clutter associated with radar pulses that an airborne radar receives from a radar transponder | Interfering clutter in radar pulses received by an airborne radar system from a radar transponder can be suppressed by developing a representation of the incoming echo-voltage time-series that permits the clutter associated with predetermined parts of the time-series to be estimated. These estimates can be used to estimate and suppress the clutter associated with other parts of the time-series | Ormesher Richard C. (Albuquerque, NM), Axline Robert M. (Albuquerque, NM) | Sandia Corporation (Albuquerque, NM) | 25.10.2006 | 02.12.2008 | G01S7/292, G01S13/74, G01S7/285, G01S13/00, G01S7/292, G01S13/765, G01S13/90 | 11/586465 |
| 36 | 7315485 | System and method for target classification and clutter rejection in low-resolution imagery | A system and method of determining a classification of at least one underwater object is provided. The method includes generating at least one low-resolution imagery of an object from a plurality of frequencies produced by a detection device and extracting at least 5 characteristics of the object within the low-resolution imagery at each of the plurality of frequencies. The method further includes generating at least 15 features from the at least 5 characteristics and classifying the features to determine the identity of the at least one underwater object | Stack Jason (Panama City Beach, FL), Dobeck Gerald (Panama City, FL) | United States of America as represented by the Secretary of the Navy (Washington, DC) | 20.12.2005 | 01.01.2008 | G03B42/06, G01S15/89, G01S7/539, G01S15/102, G03B42/06, G06K9/3241, G06K9/6218 | 11/326672 |
| 37 | 7315324 | Motion clutter suppression for image-subtracting cameras | Embodiments of the present invention relate to systems and methods for minimizing motion clutter in image-generation devices. Temporally-interleaved image-subtraction reduces the magnitude of motion clutter and has no adverse effect on the desired ambient-light cancellation of static images. Embodiments of image-generation devices employing temporally-interleaved image-subtraction include single, double, triple, and series accumulator configurations. All four embodiments allow synchronization with scene illuminators and may be implemented on a single electronic chip. Temporally-interleaved image-subtraction is particularly well suited for use in video eyetracking applications where ambient light and scene motion can cause significant problems | Cleveland Dixon (Annandale, VA), Joyce, III Arthur W. (Vienna, VA), Family ID | --- | 14.08.2003 | 01.01.2008 | H04N5/228, H04N5/238, G06T5/001, G06T5/50, G06T7/2053, H04N5/21, H04N5/23254 | 10/640248 |
| 38 | 7307575 | Through-the-wall frequency stepped imaging system utilizing near field multiple antenna positions, clutter rejection and corrections for frequency dependent wall effects | Lower resolution and clutter-prone two-tone CW radars can have the displayed images dramatically improved by three techniques involved in the subject invention. The three techniques involved are the stepping of each of the multiple radars for readings at multiple frequencies, weighting the results to compensate for wall-induced distortions and differential image processing. In one embodiment, weights for each frequency counteract the distortion produced by particular wall. For differential image processing, temporal snapshots of the images are subtracted one from the other such that the result is only due to moving objects, thus to provide a dramatic display of the presence and position of moving individuals behind a wall | Zemany Paul D. (Amherst, NH) | BAE Systems Information and Electronic Systems Integration Inc. (Nashua, NH) | 20.06.2005 | 11.12.2007 | G01S13/52, G01S13/538, G01S13/32, G01S13/56, G01S13/87, G01S13/888, G01S13/89 | 11/156948 |
| 39 | 7298316 | Apparatus and method for instantly automatic detecting clutter blocks and interference source and for dynamically establishing clutter map | An apparatus for detecting clutter blocks and an interference source for dynamically establishing a clutter map includes a clutter block detecting module accumulates a plurality of range cell data of each detecting area, and compares the accumulated value with a clutter block level to define the position of a clutter block: a interference source detecting module accumulates all range cell data in each radar beam area, and compares the accumulated value with an interference source reference level to detect whether any interference source exists: and a clutter map establishing module saves the clutter maps on different beam areas in three memory blocks. When one clutter map cell is extracted, the clutter map cells on different beam areas neighboring with the beam area saving extracted clutter map cell are also extracted. The largest value among the extracted clutter map cells is being a clutter threshold value of a detected target | Tsai Ming-Fa (Taipei Hsien, TW), Chang Zheng-Cheng (Taoyuan, TW), Chen Ming-Wey (Taoyuan, TW) | Chung Shan Institute of Science and Technology, Armaments Bureau M.N.D. (Taoyuan, TW) | 19.12.2005 | 20.11.2007 | G01S13/00, G01S13/52, G01S7/2922, G01S7/414 | 11/314789 |
| 40 | 7286079 | Method and apparatus for detecting slow-moving targets in high-resolution sea clutter | An apparatus for non-coherently detecting slow-moving targets in high resolution sea clutter includes a binary detector for converting high resolution radar returns, produced in response to a radar pulse scan of a plurality of identical pulses, into corresponding binary outputs based on a comparison of range cell magnitudes with a detector threshold. A range extent filter converts these binary outputs into an output indicating the presence or absence of a cluster of the returns that are closely spaced in range, while a third, persistence integration stage determines target range extent persistence over a predetermined time period. A detector stage declares detection of a target based on a comparison of the output of the third stage with a selected threshold | Blunt Shannon D. (Alexandria, VA), Gerlach Karl R. (Chesapeake Beach, MD) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 21.04.2005 | 23.10.2007 | G01S7/292, G01S13/52, G01S13/534, G01S7/2927, G01S7/414 | 11/110737 |
| 41 | 7249326 | Method and system for reducing notification area clutter | A method and system are provided for use in a computer system for organizing and displaying notification items associated with the system, applications or other components, within a notification area. The system monitors items that are placed in the notification, comparing the period of placement with a predetermined time threshold value, If the item has remained inactive for longer than the predetermined threshold period, the item is hidden from the notification area. Additionally, the system monitors the hidden items for changes in icon appearance and will unhide the item upon a change in appearance or specific selection by a user. New addition to the notification area. The system also allows a user to customize the behavior associated with individual notification items | Stoakley Richard W. (Seattle, WA), Kurtz James B. (Bellevue, WA), Green Todd J. (Seattle, WA), Ramasubramanian Ramkumar (Redmond, WA), Guzak Chris J. (Kirkland, WA), Springfield James F. (Woodinville, WA) | Microsoft Corporation (Redmond, WA) | 04.04.2001 | 24.07.2007 | G06F3/00, G06F3/0481, G06F3/04817 | 09/825717 |
| 42 | 7236124 | Radar system and method for reducing clutter in a high-clutter environment | A radar system transmits an environment-sensing pulse and processing convolution matrix from the radar return samples resulting from a transmission of the environment-sensing pulse. The processing circuitry may also generate a plurality of return energy-ranked vectors from a decomposition of the convolution matrix. The processing circuitry may select one of the return energy-ranked vectors for generation of a clutter-orthogonal transmit waveform. In some embodiments, the processing circuitry may select a clutter-orthogonal vector from the plurality of return energy-ranked vectors and may quantize the clutter-orthogonal vector for application to the phase modulator for generation of the clutter-orthogonal transmit waveform. The radar system may perform multiple correlations on sampled radar returns from the clutter orthogonal transmit waveform using a family of pseudo-orthogonal waveforms to detect a slow-moving target | Adams Vinh (Tucson, AZ), Dwelly Wesley (Tucson, AZ), Adams Robert J. (Tucson, AZ) | Raytheon Company (Tucson, AZ) | 02.06.2005 | 26.06.2007 | G01S13/52, G01S13/00, G01S7/282, G01S7/4008, G01S7/414 | 11/143045 |
| 43 | 7154433 | Method and device for the detection and track of targets in high clutter | A method for discriminating and tracking a target in a clutter cloud includes transmitting a radar signal at a signal bandwidth to:identify a range extent of a clutter cloud: determine a centroid and a velocity growth rate of the clutter cloud: and identify a direction of movement of the centroid of the clutter cloud. The method may also include locking a another radar signal having a greater signal bandwidth onto the centroid of the clutter cloud whereby the centroid is tracked within one radar range resolution bin: providing a delay line that includes at least two Doppler filters and is configured to cover a Doppler frequency range corresponding to a velocity growth rate of the clutter cloud: and processing a reflected radar signal corresponding to the greater signal bandwidth. The processing of the reflected radar signal may comprise passing the reflected radar signal through the delay line to mitigate a portion of the reflected signal that is reflected by the clutter cloud. A system and apparatus for performing the method is also provided | Madewell J. Michael (Madison, AL) | The United States of America as represented by the Secretary of the Army (Washington, DC) | 21.04.2004 | 26.12.2006 | G01S13/52, G01S13/24, G01S13/5246, G01S13/526, G01S13/53, G01S13/532 | 10/830805 |
| 44 | 7095358 | Technique for cancellation of elevated clutter for the detection of fixed and ground moving targets under trees | A target is detected under a forest canopy or other elevated clutter where the target is obscured by the elevated clutter. Radar returns reflected from the target on the surface, combined with those from the elevated clutter are digitized. Motion compensation is performed for the radar returns with respect to the target to obtain a focused first synthetic aperture image of the target. Next, the radar returns are motion compensated with respect to the elevated clutter at various heights above the surface to obtain images of the elevated clutter. The elevated clutter within the images at the various heights above the surface is identified and coherently subtracted from the original synthetic aperture images | Krikorian Kapriel V. (Calabasas, CA), Rosen Robert A. (Simi Valley, CA) | Raytheon Company (Waltham, MA) | 23.11.2004 | 22.08.2006 | G01S13/90, G01S7/292, G01S13/90 | 10/996024 |
| 45 | 7058887 | Audio clutter reduction and content identification for web-based screen-readers | A method and apparatus for reading a web page according to a set of user-configurable settings. In one embodiment, a set of user-configurable settings configured for reading the web page is determined. An initial reading position on the web page is determined as specified by the user-configurable settings. The web page is then read from the initial reading position according to the set of user-configurable settings | Cragun Brian John (Rochester, MN) | International Business Machines Corporation (Armonk, NY) | 07.03.2002 | 06.06.2006 | G06F15/00, G10L13/08 | 10/093159 |
| 46 | 7030805 | Methods and system suppressing clutter in a gain-block, radar-responsive tag system | Methods and systems reduce clutter interference in a radar-responsive tag system. A radar transmits a series of linear-frequency-modulated pulses and receives echo pulses from nearby terrain and from radar-responsive tags that may be in the imaged scene. Tags in the vicinity of the radar are activated by the radar's pulses. The tags receive and remodulate the radar pulses. Tag processing reverses the direction, in time, of the received waveform's linear frequency modulation. The tag retransmits the remodulated pulses. The radar uses a reversed-chirp de-ramp pulse to process the tag's echo. The invention applies to radar systems compatible with coherent gain-block tags. The invention provides a marked reduction in the strength of residual clutter echoes on each and every echo pulse received by the radar. SAR receiver processing effectively whitens passive-clutter signatures across the range dimension. Clutter suppression of approximately 14 dB is achievable for a typical radar system | Ormesher Richard C. (Albuquerque, NM), Axline Robert M. (Albuquerque, NM) | SANDIA Corporation (Albuquerque, NM) | 23.07.2004 | 18.04.2006 | G01S13/74, G01S13/76, G01S13/282, G01S13/90 | 10/898119 |
| 47 | 7006034 | Fast and slow time scale clutter cancellation | Target detection in the presence of non stationary clutter is improved by a radar receiver on a moving platform for detecting a target using a plurality of short coherent arrays and a plurality of long coherent arrays synthesized from the short coherent arrays overlapping the target. The target is obscured by slow scale clutter and fast scale clutter in the vicinity of the target. The radar receiver has a plurality of subapertures overlapping to acquire radar returns reflected from the target during the arrays, an analog to digital converter for each of the subapertures to convert the radar returns into digital radar returns for a plurality of range bins covering the target, the slow scale clutter and the fast scale clutter: and a digital computer for performing steps of SAR image creation, further enhanced by thresholding short array magnitude data, computing a time domain component of threshold filters using the thresholded short array magnitude data then coherently subtracting the time domain component of threshold filters from the short arrays, and using the result to synthesize long coherent arrays. A Space Time Adaptive Algorithm (STAP) is applied to the long coherent arrays thus obtained to suppress slow and stationary clutter. The short coherent arrays are between 10 and 400 milliseconds long. The long coherent arrays are between 400 and 4000 milliseconds long | Krikorian Kapriel V. (Calabasas, CA), Rosen Robert A. (Simi Valley, CA), Krikorian Mary (Calabasas, CA) | Raytheon Company (Waltham, MA) | 10.03.2005 | 28.02.2006 | G01S7/292, G01S13/00, G01S13/90, G01S13/9029 | 11/077093 |
| 48 | 6999025 | Clutter rejection in a passive radar receiver of OFDM signals with antenna array | The invention concerns a passive radar receiver with an array of antennas for a OFDM received signal comprising frames of symbols each emitted on coded orthogonal carriers. After formatting received signals into digital symbols, dummy signals from dummy OFDM emitters at different distances from and in different directions relative to the receiver are generated and added to the signals picked up by the antennas. The modified received eliminate at least unwanted zero Doppler effect signals and to provide an isotropic reception diagram without blind sector of direct path being generated and by detecting mobile targets along the direct path | Poullin Dominique (Chatillon, FR) | Onera (Chatillon, FR) | 19.02.2002 | 14.02.2006 | G01S13/528, G01S7/414, G01S13/003, G01S13/524, G01S13/24 | 10/469188 |
| 49 | 6997876 | Ultrasound clutter filtering with iterative high pass filter selection | A system and method for ultrasound clutter filtering is provided. A processor is configured to iteratively select an optimal high pass filter flow imaging data. The high pass filter input for each iterative ultrasound color flow imaging data. The high pass filters have different cutoff frequencies whereby each high pass filter can be implemented using different structures. The system and method allow for filtering of clutter from ultrasound color flow imaging data until the clutter is substantially removed | Mo Larry Y. L. (San Ramon, CA), Chou Ching-Hua (Fremont, CA), Ji Ting-Lan (San Jose, CA), McLaughlin Glen W. (Saratoga, CA) | Zonare Medical Systems, Inc. (Mountain View, CA) | 16.04.2004 | 14.02.2006 | A61B8/06, A61B8/00, A61B8/4438, A61B8/462, A61B8/465, A61B8/467, G01S7/52084, G01S15/8981, A61B8/06, A61B8/08, A61B8/0833, A61B8/0866, A61B8/13, A61B8/4455, A61B8/468, A61B8/488 | 10/825719 |
| 50 | 6924763 | Clutter rejection in a passive radar receiver of OFDM signals | The invention concerns a passive radar receiver for a received orthogonal frequency division multiplex-type signal consisting of symbol frames each emitted on coded orthogonal carriers. After formatting the received signals into digital symbols (S.sub.1 S.sub.1), a filtering circuit (2) eliminates by subtraction or using a covariance matrix, in the symbol signal at least unwanted signals with null Doppler effect so as to apply a filtered signal (X') including essentially signals backscattered by mobile targets to a Doppler-distance correlator (4) | Poullin Dominique (Chatillon, FR) | ONERA (Chatillon, FR) | 30.07.2003 | 02.08.2005 | G01S13/00, G01S13/524, G01S7/02, G01S7/41, G01S007/41, G01S007/42, G01S7/414, G01S13/003, G01S13/524 | 10/470713 |
| 51 | 6861974 | Clutter normalization by adaptation of transmit waveform | A radar, sonar, lidar or like active detection, tracking system calculates the clutter which would occur with various different transmit waveforms, and selects from among those waveforms that one which, given the current clutter, is expected to minimize variation or variability of the clutter. The calculation is performed by generating a clutter kernel for the current transmitted or other reference waveform, and calculating the clutter which would result with alternate transmit waveform(s). The variability of the various clutter responses is determined, and the transmit waveform exhibiting the least clutter variability is selected for a later transmission | Poe Randall Charles (Morton, PA), Hein Carl Edward (Cherry Hill, NJ) | Lockheed Martin Corporation (Bethesda, MD) | 16.10.2003 | 01.03.2005 | G01S7/02, G01S7/41, G01S7/40, G01S013/12, G01S7/4008, G01S7/414 | 10/687379 |
| 52 | 6809682 | Method and device for the detection and track of targets in high clutter | A method for discriminating and tracking a target in a clutter cloud includes transmitting a radar signal at a signal bandwidth to:identify a range extent of a clutter cloud: determine a centroid and a velocity growth rate of the clutter cloud: and identify a direction of movement of the centroid of the clutter cloud. The method may also include locking a another radar signal having a greater signal bandwidth onto the centroid of the clutter cloud whereby the centroid is tracked within one radar range resolution bin: providing a delay line that includes at least two Doppler filters and is configured to cover a Doppler frequency range corresponding to a velocity growth rate of the clutter cloud: and processing a reflected radar signal corresponding to the greater signal bandwidth. The processing of the reflected radar signal may comprise passing the reflected radar signal through the delay line to mitigate a portion of the reflected signal that is reflected by the clutter cloud. A system and apparatus for performing the method is also provided | Madewell J. Michael (Madison, AL) | The United States of America as represented by the Secretary of the Army (Washington, DC) | 16.01.2003 | 26.10.2004 | G01S13/24, G01S13/524, G01S13/526, G01S13/53, G01S13/00, G01S13/532, G01S013/52, G01S13/24, G01S13/5246, G01S13/526, G01S13/53, G01S13/532 | 10/346157 |
| 53 | 6771207 | Establishing radar coverage, blockage, and clutter region maps for radar product data based on terrain elevation data | Radar coverage maps having blockage, coverage and clutter features available for ease of interpretation are provided using terrain data to establish such features in data sets. The data sets provide a basis for the modified display. Multiple tilts of the radar scan may be represented. Multiple radar zones may be overlapped to provide a mosaic of a region showing areas of no coverage despite overlap | Lang Joseph C. (Havortown, PA) | Unisys Corporation (Blue Bell, PA) | 25.06.2003 | 03.08.2004 | G01S13/95, G01S13/00, G01S7/40, G01S013/00, G01S7/4004, G01S13/951 | 10/606341 |
| 54 | 6750804 | System and method for detecting and estimating the direction of near-stationary targets in monostatic clutter using phase information | A system and method for detecting a target. The inventive method includes the steps of receiving a complex return signal of an electromagnetic pulse having a real and an imaginary component: extracting from the imaginary component information representative of the phase component of the return signal: and utilizing the phase component to detect the target. Specifically, the phase components are those found from the complex range-Doppler map. More specific embodiments further include the steps of determining a power spectral density of the phase component of the return signal: performing a cross-correlation of power spectral density of the phase component of the return signal between different antenna-subarray (quadrant channels): and averaging the cross-correlated power spectral density of the low frequency components. In an alternative embodiment, the cross-correlation is performed on the phase component of the range-Doppler map directly. This signal can then be averaged to potentially provide improved detection of targets. The cross-correlations of the power spectral densities derived from the complex valued range-Doppler map are then used to detect the target in the presence of monostatic clutter. An additional teaching relates to a utilization of the phase component to ascertain a direction of the target and thereby effect target tracking as well as target detection | Chen Hai-Wai (Tucson, AZ), Schmitt Harry A. (Tucson, AZ), David George T. (late of Oro Valley, AZ), Braunreiter Dennis C. (Oro Valley, AZ), Samuel Alphonso A. (Tucson, AZ) | Raytheon Company (Waltham, MA) | 04.04.2002 | 15.06.2004 | G01S13/524, G01S13/00, G01S13/88, G01S7/288, G01S7/285, G01S007/292, G01S007/28, G01S007/285, G01S013/00, G01S13/5244, G01S13/883, G01S2007/2883, G01S2007/2886 | 10/116438 |
| 55 | 6747593 | Generalized clutter tuning for bistatic radar systems | A system and method for controlling clutter Doppler spread in a bistatic radar system is developed resulting in enhanced detection of low-Doppler targets or improved SAR mode performance. In an illustrative embodiment, a bistatic radar system (10) includes a transmitter (12) for transmitting electromagnetic energy (106) towards a target (16), a receiver (14) adapted to receive the electromagnetic energy (116) reflected from the target (16), and a processor (122) for optimizing a parameter or parameters of the system such that the directional derivative of the bistatic Doppler field along the isorange contour is near a desired value. The parameters to be optimized may include the transmitter velocity vector, the receiver velocity vector, or the receiver azimuth flight direction. The desired value is the minimal absolute value of the maximize the clutter Doppler spread | Jaffer Amin G. (Fullerton, CA) | Raytheon Company (Waltham, MA) | 26.06.2003 | 08.06.2004 | G01S13/524, G01S13/00, G01S13/90, G01S013/00, G01S007/292, G01S13/003, G01S13/524, G01S13/9035 | 10/609029 |
| 56 | 6733455 | System and method for adaptive clutter filtering in ultrasound color flow imaging | An adaptive clutter filtering for ultrasound color flow imaging is provided including an iterative algorithm that is used to select the best clutter filter for each packet of color flow data. If significant clutter motion is present, a high pass filter cutoff frequency is automatically set to suppress the clutter and associated flash artifacts. The cutoff frequency is chosen according to the frequency of the clutter--the lower the clutter frequency, the lower the cutoff frequency can be. If clutter frequencies are low, lower filter cutoffs allow for maximum low flow detection. In this manner, the filter cutoff frequency can be optimized based on the data for each pixel in the color flow image | Mo Larry Y. L. (San Ramon, CA), Chou Ching-Hua (Fremont, CA), Ji Ting-Lan (San Jose, CA), McLaughlin Glen W. (Saratoga, CA) | Zonare Medical Systems, Inc. (Mountain View, CA) | 11.06.2002 | 11.05.2004 | A61B8/08, G01S15/89, G01S15/00, A61B8/06, A61B008/06, A61B8/00, A61B8/4438, A61B8/462, A61B8/465, A61B8/467, G01S7/52084, G01S15/8981, A61B8/06, A61B8/08, A61B8/0833, A61B8/0866, A61B8/13, A61B8/4455, A61B8/468, A61B8/488 | 10/167606 |
| 57 | 6720910 | Pri-staggered post-doppler adaptive monopulse processing for detection and location of a moving target in ground clutter | A method, apparatus, and processing system for radar detection and tracking of a target using monopulse ratio processing comprising the following steps. First, receiving a signal comprised of a plurality of sum azimuth beams and difference azimuth beams. Then staggering the received signal. Next, filtering and localizing a clutter signal which is a portion of the received sum and azimuth beams. Then adaptively forming a sub-array sum azimuth beam and a sub-array difference azimuth beam from the filtered output to cancel the clutter. The adaptive beam forming including the determination of a sum and difference beam weight where the adaptive weight be equated to a product of the weight and the respective covariance matrices of the sum and difference beams, the product having no constraint points. Finally, forming a final sum azimuth beam and final difference beam where the first sub array is related to the sum and azimuth beams of a plurality of other sub-array sum and difference beams, an overall final sum beam is formed and is used for target detection. In addition, an overall final difference beam is formed and the ratio of the overall final difference beam to the overall final sum beam is used for angle location determination | Yu Kai-Bor (Niskayuna, NY) | Lockheed Martin Corporation (Bethesda, MD) | 16.08.2001 | 13.04.2004 | G01S13/00, G01S13/44, G01S13/22, G01S013/52, G01S013/00, G01S13/4463, G01S13/449, G01S13/225 | 09/930891 |
| 58 | 6689064 | Ultrasound clutter filter | A method for adaptive filtering of clutter from a sample stream having a blood signal component and a clutter signal component comprises the steps of (a) estimating a signal strength of the sample stream, and (b) signal strength estimate and a signal strength threshold. The filter receives the sample stream and provides an output stream having a reduced level of the clutter signal component relative to the blood signal component | Hager Richard A (Derry, NH), Clark David W (Windham, NH), Thiele Karl E (Andover, MA), Witt Jerome F (Andover, MA) | Koninklijke Philips Electronics N.V. (Eindhoven, NL) | 22.06.2001 | 10.02.2004 | G01S15/00, G01S15/89, G01S7/52, A61B008/12, G01S7/52026, G01S15/8981 | 09/887648 |
| 59 | 6677886 | Weather and airborne clutter suppression using a cluster shape classifier | A method of determining the presence of a weather or other airborne (non-aircraft) clutter in a radar detection system is disclosed. The method includes feature calculations of a cluster of detections, and characterizing the cluster. Confidence factors are determined from the characterization of a cluster and a determination is made from the confidence factors whether the cluster represents a real aircraft or a false target | Lok Yuchoi Francis (Framingham, MA) | Raytheon Company (Lexington, MA) | 28.10.2002 | 13.01.2004 | G01S13/95, G01S13/91, G01S7/02, G01S13/00, G01S7/41, G01S013/95, G01S7/414, G01S13/91, G01S13/95 | 10/281573 |
| 60 | 6665542 | System and method for cumulative clutter path loss | A method and system of determining the cumulative clutter path loss between two points within a coverage area (30) of a telecommunications network. The coverage area of the network is divided into a geographical matrix of bins (31). For each bin in the matrix, a clutter value is assigned indicating the appropriate losses a signal experiences as it propagates through the bin. The clutter values of bins (31) in the matrix are added along a radial (21) connecting the two points to determine a cumulative clutter path loss between a transmitter and a receiver, such as a base station (20) and mobile handset (28) | Clancy James G. (Plano, TX) | Telefonaktiebolaget LM Ericsson (publ), (Stockholm, SE) | 07.09.2000 | 16.12.2003 | H04Q7/36, H04B007/01, H04W16/18 | 09/656596 |
| 61 | 6657195 | Clutter discriminating focal plane arrays | A quantum well infrared photodetector focal plane array is disclosed wherein each detector structure of the array comprises two vertically stacked quantum well layers. Each of the quantum well layers are individually biased by separate bias voltages and the separate bias voltages are modulated to produce two or more measurements at different spectral bands. Each detector structure of the array can therefore perform measurements of incident infrared energy in at least four separate spectral bands. This technique of measuring incident infrared energy in four separate spectral bands can advantageously be applied to the discrimination of hot gas sources from background infrared clutter | Martin Robert J. (Orlando, FL), Loefer Gene Raymond (Orlando, FL) | Lockheed Martin Corporation (Bethesda, MD) | 21.09.2000 | 02.12.2003 | H01L31/09, H01L31/08, H01L031/09, B82Y20/00, G01J3/42, H01L27/14652, H01L31/035236 | 09/665959 |
| 62 | 6603425 | Method and system for suppressing ground clutter returns on an airborne weather radar | A system and method for suppressing ground clutter in avionics weather radars which includes automatically making multiple scans, closely spaced in time and space, and comparing the returning signals to known ground return signals over known tilt angle variations | Woodell Daniel L. (Robins, IA) | Rockwell Collins, Inc. (Cedar Rapids, IA) | 22.09.2000 | 05.08.2003 | G01S13/95, G01S13/00, G01S7/02, G01S7/41, G01S13/524, G01S7/292, G01S013/95, G01S7/414, G01S13/953, G01S7/2925, G01S13/5244 | 09/668656 |
| 63 | 6580911 | Clutter database enhancement methodology | An enhanced clutter database and modeling tool are provided for use in determining the propagation characteristics and requisite transmitted signal strengths for physical regions having attenuating objects therein. The enhanced clutter database supports a plurality of different resolution levels and can therefore be used to adjust transmission requirements for both large and small coverage areas. A plurality of bins and sub-bins are defined and values provided for in the enhanced clutter database to further distinguish clutter types within portions of the coverage area. Adjustment of the transmission requirements can be manually initiated or automatically conducted using the enhanced clutter database. The enhanced clutter database is populated by fusing geographical data with more detailed supplemental physical environment data provided by one or more data collection services | Clancy James G. (Plano, TX) | Ericsson Inc. (Research Triangle Park, NC) | 06.08.1999 | 17.06.2003 | H04Q7/22, H04Q7/38, H04Q007/20, H04W16/18 | 09/369791 |
| 64 | 6426718 | Subaperture processing for clutter reduction in synthetic aperture radar images of ground moving targets | A radar tracking system extracts moving target content from a single radar pulse stream. The radar tracking system has a single phase center antenna for receiving the radar pulse stream. The tracking system further includes a signal processing system for converting the radar pulse stream into a plurality of SAR images. Each image has a corresponding moving target content and a corresponding clutter content. The tracking system also includes a targeting system for canceling identical clutter content between the images. The signal processing system includes a synthetic subaperture system for generating a plurality of synthetic subapertures and defining a common reference point. The common reference point has known slant ranges with respect to the plurality of synthetic subapertures. A deramping module uses a unique deramping function to compute a deramped signal for each synthetic subaperture based on the known slant ranges. The signal processing system further includes an imaging system for generating SAR images for the deramped signals. The processing of a radar pulse stream from a single antenna allows antenna size to be reduced by a factor of two or more, and allows tracking of slowly moving targets | Ridgway Robert I. (San Jose, CA) | The Boeing Company (Chicago, IL) | 14.03.2000 | 30.07.2002 | G01S13/00, G01S13/90, G01S13/534, G01S013/534, G01S13/534, G01S13/9029 | 09/525642 |
| 65 | 6380887 | Method of reducing clutter and mutual interference in a coherent doppler radar system | A method is proposed for use on a coherent Doppler radar system for the purpose of reducing the clutter and mutual interference in the coherent Doppler radar system. The echoed radar signal from the target object is converted into a Range-Doppler Domain output signal. If the Range-Doppler Domain output signal indicates the presence of mutual interference, a Crisscrossing CFAR method is selected to compute for the CFAR back-ground value: otherwise an Area CFAR method is selected. A target-detection logic circuit is then used to obtain the radar information about the target object. By the proposed method, the output signal of the target-detection logic circuit is substantially free from clutter and mutual interference, which is further converted into a radar display signal to drive a radar display unit to display the location and velocity of the target object | Suen Tain-Wen (Taichung Hsien, TW) | Chung-Shan Institute of Science and Technology (Taoyuan, TW) | 08.03.2000 | 30.04.2002 | G01S13/00, G01S13/524, G01S13/532, G01S7/292, G01S7/288, G01S7/285, G01S013/53, G01S7/2923, G01S13/5246, G01S13/532, G01S7/288 | 09/520417 |
| 66 | 6377206 | Method for clutter rejection in digital imagery | A method for filtering clutter from a first digital input image is disclosed. Generally, the method includes the steps of applying at least first and second transforms to first digital image data corresponding to the first digital input image, performing an appropriate filtering operation to retain, in first and second transform domains, at least a portion of the transform indications corresponding or at least correlatable to a structure or target in the first digital input image, applying to the remaining transform indications inverse first and second transforms, and processing the filtered first digital input data to produce a single filtered image and/or image data, whereby the target or structure in the first digital input image formerly obscured by the clutter is detectable/recognizable | Petty Joe V. (Highlands Ranch, CO) | Lockheed Martin Corporation (Bethesda, MD) | 06.04.2000 | 23.04.2002 | G06T5/10, G06T5/00, G01S3/786, G01S3/78, G01S007/292, G06T5/001, G06T5/10, G01S3/7865 | 09/544506 |
| 67 | 6309357 | Medical diagnostic ultrasound system and method for improved flow or movement detection with multiple clutter filters | A method and system for flow or movement detection is provided. More than one clutter filter is used. Each clutter filter's magnitude versus frequency response is optimized differently. Estimates of the flow or movement are generated from the data output by each of the clutter filters. Using selection or combination of the resulting estimates, the best attributes of each filter are used for imaging | Guracar Ismayil M. (Redwood City, CA), Phillips Patrick J. (Sunnyvale, CA) | Acuson Corporation (Mountain View, CA) | 09.08.1999 | 30.10.2001 | G01S15/89, G01S15/00, G01S7/52, A61B8/08, A61B8/06, A61B008/00, G01S7/52025, G01S7/52049, G01S15/8909, G01S15/8981, A61B8/06, A61B8/08 | 09/370758 |
| 68 | 6224557 | Ultrasonic method using adaptive clutter filter to remove tissue wall motion | The method of the invention controls an ultrasound system that implements a clutter filter, to derive parameters such as blood flow velocity, echo power and/or echo amplitude data from an anatomical region of interest (ROI) and into which a contrast agent has been introduced. The method initially transmits an ensemble of N ultrasound beams along a common azimuth and elevation into the ROI to cause destruction of the contrast agent lying along the azimuth. Estimated wall motion velocity data is then derived for the tissue wall region through use of selected echo signal data derived from a subset of the N ultrasound beams of the ensemble, the subset excluding echo signal data from a first M of the N ultrasound beams or any subset of the N ultrasound beams. The clutter filter is then adjusted to attenuate selected echo signal data returned from the ROI that exhibits the wall motion velocity data. The wall motion data derived from the N ultrasound beams or a subset thereof is processed by the adjusted clutter filter to derive echo data that is better indicative of echo signal returns from the contrast agent or blood flow and is less indicative of wall motion effects | Ziel J Mark (North Andover, MA), Thiele Karl E (Andover, MA) | Agilent Technologies, Inc. (Palo Alto, CA) | 03.02.2000 | 01.05.2001 | A61B8/06, G01S15/89, G01S15/00, G01S7/52, A61B008/00, A61B8/06, A61B8/13, G01S7/52038, G01S15/8981 | 09/497579 |
| 69 | 6146331 | Method for improved clutter suppression for ultrasonic color doppler imaging | A Doppler ultrasound clutter suppression system and method in which the clutter is first low-pass filtered (716) to suppress the flow component (4024) just before mean frequency estimation (718). The mean frequency is then estimated and mixed with the original clutter data which is positioned at DC. The low-pass filter bandwidth is predetermined based on the particular application and imaging parameters. The signal is then high-pass filtered (726) to remove the clutter component (4022) | Wong Tommy (Issaquah, WA) | Siemens Medical Systems, Inc. (Iselin, NJ) | 30.09.1998 | 14.11.2000 | A61B8/06, G01S15/89, G01S15/00, A61B008/00, A61B8/06, A61B8/13, G01S15/8981, G01S15/8988 | 09/164386 |
| 70 | 6137439 | Continuous wave doppler system with suppression of ground clutter | In a continuous wave Doppler system in which a fixed transmitter transmits a continuous wave signal to be reflected by moving targets and by fixed structure, an aircraft receives the reflective signals at two spaced apart antennas. The signals reflected from moving targets are distinguished from ground clutter reflected from fixed structure by the phase difference between the Doppler signals receive by the two antennas. The signals reflected from moving targets are distinguished from the ground clutter in response to the phase difference between the Doppler signals received by the two antennas being not equal to a phase difference value determined to be the phase difference for clutter signals. The phase difference value for clutter signals is determined from a function expressing the phase difference value as a linear variation with the Doppler frequency of the signals | Bradford Bert L. (Damascus, MD), Lodwig Richard A. (Gaithrsburg, MD) | Lockheed Martin Corporation (Bethesda, MD) | 08.09.1998 | 24.10.2000 | G01S13/00, G01S13/536, G01S13/66, G01S013/00, G01S007/493, G01S007/536, G01S13/003, G01S13/536, G01S13/66 | 09/148988 |
| 71 | 6130639 | Method for fine modelling of ground clutter received by radar | A process for modelling of ground clutter received by a radar, starting from a meshed numerical terrain model, including identifying cells from the meshed numerical terrain model which comprise elements having a height greater than a resolution of the model: determining, for relevant cells, an average height of the elements: sectioning the relevant cells into height-wise slices: and calculating power backscattered by each of the relevant cells by representing contents thereof with elementary reflectors distributed over an entire height thereof as a function of adjoining cells and a profile of terrain situated between the radar and a relevant cell | Agnesina Eric (Antony, FR), Henry Jean-Philippe (Vanves, FR), Le Hellard Daniel (Nantes, FR), Moruzzis Michel (La Norville, FR) | Thomson-CSF (Paris, FR) | 28.09.1998 | 10.10.2000 | G01S7/40, G01S007/40, G01S7/4052 | 09/155411 |
| 72 | 6127965 | Method and apparatus for rejecting rain clutter in a radar system | A method and apparatus for detecting the presence of objects in a vehicle operator's blind spots. The apparatus comprises a side-facing Doppler radar system using continuous wave (CW) transmission with frequency modulation (FM) operation from a frequency modulation switching technique. The radar system determines the presence, range and closing rate of detected targets. The radar system detects targets even when operated in adverse weather conditions and will not generate false warnings due to rain clutter caused by wet roads and other wet surroundings. The radar system uses ranging techniques to reject false targets that are detected outside of a predetermined target detection zone. In accordance with the present invention, the radar system indicates that a target is detected if and only if any part of the target is within the detection zone and it: (1) remains in front of the antenna for at least TH1 seconds: (2) is at a range between Range.sub.min and Range.sub.max : and (3) is moving faster than Closing-Speed.sub.min relative to the antenna. By rejecting targets that are closer than Range.sub.min feet to the antenna, false alarms due to rain clutter are dramatically reduced. Also, by rejecting targets that are further than Range.sub.max feet from the antenna, the radar system reduces false alarms caused by wet foliage and other wet "non-road" surroundings. In one embodiment, the radar system uses a patch array antenna oriented into a diamond-shape configuration to effectively create a natural linear amplitude taper that aids in rejecting clutter caused by wet road surfaces | McDade James C. (Poway, CA), Stone Robert E. (San Diego, CA), Bohley Eric P. (Escondido, CA), Schlichtig Roger J. (Westlake Village, CA) | Eaton-VORAD Technologies, L.L.C. (San Diego, CA) | 23.07.1998 | 03.10.2000 | G01S13/00, G01S13/93, G01S13/34, G01S13/32, G01S7/02, G01S7/41, G01S013/93, G01S013/50, G01S013/00, G01S13/931, G01S7/415, G01S13/325, G01S13/34, G01S2013/9332 | 09/122479 |
| 73 | 6081605 | Clutter rejection through edge integration | A device and method for performing clutter rejection through edge integran. The invention uses optical flow estimation to produce target centering information which is used to control an image source so that a detected moving target is maintained in the center of an image containing the target and accompanying clutter while continuous, real-time integration of the target edges is performed. The output image produced contains an enhanced target and the target to clutter ratio is, therefore, enhanced | Roth Duane (Ridgecrest, CA), Morrison Larry M. (Ridgecrest, CA) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 08.03.1993 | 27.06.2000 | G06K9/40, G06K9/32, G06K009/00, G06K9/3241, G06K9/40 | 08/028013 |
| 74 | 6064334 | Clutter resistant target detector | A ranging device is disclosed that monitors for changes in a scene of interest. The ranging device includes a transmitter that sends pulses into the scene, a receiver that generates pulse samples in response to pulse returned from the scene, and a target discriminator that analyzes the pulse samples. The target discriminator detects targets entering the scene, targets leaving the scene, and targets moving in the scene through the use of at least one non-averaging statistical characteristic of the pulse samples. The target discriminator may generate short term and long samples. The detector samples are highly indicative of the presence or absence of a target in the scene. The target discriminator may also include a post processor that evaluates the detector samples, applies additional discrimination functions to the detector samples, and determines the presence or absence of a target in the scene of interest | Ikizyan Ike A. (Downey, CA), Spieker Thomas L. (San Juan Capistrano, CA), Shreve Greg A. (San Pedro, CA) | TRW Inc. (Redondo Beach, CA) | 15.07.1998 | 16.05.2000 | G01S13/00, G01S13/524, G06K9/32, G01S7/523, G01S7/527, G01S013/526, G01S13/5246, G06K9/3241, G01S7/527 | 09/116332 |
| 75 | 6061016 | Method for the attenuation of the clutter coming from the reflection lobes of a radar antenna | The disclosed method uses the ancillary antennas of a radar, and consists in determining the positions of the phase centers of these ancillary antennas, compensating for the difference in optical path between the reflection lobe of the processed channel and that of the ancillary channel, and generating a synthetic channel by an SLO type processing in performing a coherent subtraction between the processed channel and the ancillary channels used, on the desensitized zone of the doppler distance/frequency ambiguous domain of each of the processed channels | Lupinski Ludovic (Chatillon-sous-Bagneux, FR), Regnier Bertrand (Chatenay-Malabry, FR) | Thomson-CSF (Paris, FR) | 09.11.1998 | 09.05.2000 | G01S7/28, G01S7/285, G01S013/00, G01S003/16, H01Q003/24, G01S7/2813, G01S7/285 | 09/188325 |
| 76 | 6052485 | Fractal features used with nearest neighbor clustering for identifying clutter in sonar images | A method is presented for identifying clutter in an image such as a sonar age. A detection scheme identifies portions of the image having a signal-to-noise ratio greater than a given threshold. A classification scheme is then applied to each such portion to generate fractal feature or non-target. For clutter identification, each portion is assigned to a group based on a distance from the position of each portion to another of the portions that is its nearest neighbor. A series of tests are then performed for each group using the fractal feature values associated with each portion in each group. A failure of any of the series of tests by a group identifies each portion associated with that group as clutter in the image | Nelson Susan R. (Panama City, FL), Tuovila Susan M. (Panama City, FL) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 03.02.1997 | 18.04.2000 | G06K9/32, G06K009/62, G06K9/3241 | 08/794521 |
| 77 | 5999212 | Method and apparatus for infrared detection of a moving target in the presence of solar clutter | A detection system for detecting a target flying over water, which includes a detector positioned to receive radiation reflected by the target off water, and producing a detector output signal having an amplitude proportional to the amount of received radiation, a high-pass filter for passing portions of the detector output signal having a frequency greater than a prescribed threshold frequency, and for blocking portions of the detector output signal having a frequency lower than the prescribed threshold frequency. The prescribed threshold frequency is sufficiently high to ensure that only the portions of the detector output signal produced by the radiation reflected by the target off the water are passed by the high-pass filter, and that portions of the detector output signal produced by solar glitter are not passed. In a specific embodiment, the system is designed to be installed on a ship for the purpose of detecting low-flying, fast-moving targets, such as cruise missiles | Crosby Holmes (Rockville, MD), Wardlaw Michael J. (King George, VA) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 31.07.1997 | 07.12.1999 | G01S3/78, G01S3/786, H04N005/33, H04N005/225, H04N009/64, G01S3/7864 | 08/903250 |
| 78 | 5990824 | Ground based pulse radar system and method providing high clutter rejection and reliable moving target indication with extended range for airport traffic control and other applications | An MTI radar system transmits pulses with variable interpulse time periods and is structured with a lattice filter to process return signals to identify targets while substantially rejecting static and moving clutter. The MTI radar system also operates to reject adverse effects of transmitter instability in the processing of return signals. The MTI radar system is applied as an airport traffic control in which aircraft are detected as targets | Harrison Earnest R. (Severna Park, MD) | Northrop Grumman Corporation (Los Angeles, CA) | 19.06.1998 | 23.11.1999 | G01S13/00, G01S13/524, G01S13/91, G01S013/534, G01S13/524, G01S13/91 | 09/100727 |
| 79 | 5963176 | Antenna system with edge treatment means for diminishing antenna transmitting and receiving diffraction, sidelobes, and clutter | An antenna shroud or clutter fence has edge treatment for redirecting or absorbing energy which would otherwise be diffracted in an undesired direction. The edge treatment can include an array of corrugations which are about .lambda./4 deep for scattering sidelobes. The array of corrugations can be parallel to either the E-wave component or the H-wave component. Alternatively, the edge treatment can include an array of antennas encased in a dielectric extension | Solheim Frederick (Boulder, CO), Jordan James (Boulder, CO), Wilson John (Longmont, CO) | The United States as represented by the Secretary of Commerce (Washington, DC) | 14.04.1997 | 05.10.1999 | H01Q1/52, H01Q19/02, H01Q19/00, H01Q1/00, H01Q19/10, H01Q001/32, H01Q1/526, H01Q19/021, H01Q19/10 | 08/843170 |
| 80 | 5910118 | Removal of clutter components in ultrasound color-doppler imaging | An ultrasound imaging apparatus and method in which an ultrasound signal is transmitted a plurality of times in each scanning direction and its echo is received. A Doppler signal detected from a group of echo signals consisting of a train of sequential Doppler data for each spatial sample position in each scanning direction. The amount of instantaneous changes in a phase of a clutter component included in the Doppler signal is estimated, the clutter component occurring due to reflection of the ultrasound signal from an organ. A phase of the Doppler signal is corrected using the estimated amount of instantaneous changes in the phase. A constant value corresponding to the clutter component is subtracted from the Doppler signal of which phase is corrected, information representing a blood flow is extracted based on the Doppler signal of which clutter component is removed and the extracted information is displayed in color | Kanda Ryoichi (Otawara, JP), Shiki Eiichi (Otawara, JP) | Kabushiki Kaisha Toshiba (Kawasaki, JP) | 01.10.1997 | 08.06.1999 | G01S15/89, G01S15/00, A61B008/06, G01S15/8981 | 08/942329 |
| 81 | 5909190 | Clutter rejection using adaptive estimation of clutter probability density function | A processor and method for discriminating against interference during target acquisition and reacquisition processing of densely cluttered images. The processor and method that adaptively estimates the feature probability density function of the interference from the image data. The estimated interference probability density function, along with target feature estimates are input to a Bayesian classifier that discriminates the interference from the target | Lo Thomas K. (Tucson, AZ), Johnston W. Scott (Tucson, AZ) | Raytheon Company (Lexington, MA) | 30.10.1997 | 01.06.1999 | G01S3/78, G01S3/786, G06K9/62, G06K9/32, G01S007/539, G01S3/7865, G06K9/3241, G06K9/6278 | 08/961377 |
| 82 | 5805742 | Object detection system with minimum-spanning gradient filter for scene clutter suppression | A minimum-spanning gradient filter used to suppress clutter in a target detection and tracking system. The minimum-spanning gradient filter uses subspace projection clutter suppression techniques, but does not require eigenanalysis. Model frames of data from a sensor array are stored in a memory in which the model frames do not include targets that are being detected. At start-up, a Gram-Schmidt system generates a series of unit vectors that define a clutter subspace where most of the clutter in the model frames will reside. Current frames of data from the sensor array and unit vectors from the Gram-Schmidt system are applied to a subspace projection system that removes the clutter subspace from the current frames of data. Once the original clutter subspace has been generated, a plane smoothing system updates the clutter subspace as new frames of data are added to the model frames. Current frames of data sent to the subspace projection system are centered. Additionally, a standard deviation for the pixel intensities in each frame of data is applied to a standard deviation threshold to prevent pixels that fall below the threshold from being updated in the clutter subspace. A glint threshold detector is provided to eliminate pixels above a predetermined glint threshold so that they do not contribute to the updated clutter subspace | Whitsitt Stephen J. (Manhattan Beach, CA) | TRW Inc. (Redondo Beach, CA) | 16.08.1995 | 08.09.1998 | G02B5/20, G01S3/78, G01S3/786, G01S3/781, G06K009/40, G06K009/00, G01S3/781, G01S3/786, G02B5/205 | 08/624304 |
| 83 | 5805106 | Dual polarization wave clutter reduction | A system 10 for reducing clutter in passive radiometric images of the ocean surface, the system including:a first polarizer 12 for generating a vertically polarized image of a selected patch of the ocean surface, the vertically polarized image including a first set of radiance data: a second polarizer 14 for generating a horizontally polarized image of the selected patch of the ocean surface, the horizontally polarized image including a second set of radiance data: a processor 16 for computing a clutter reduction weighting factor from the first and the second sets of radiance data: and means 18 for combining the first set of radiance data with the second set of radiance data utilizing the weighting factor to generate a combined image with reduced wave clutter. The processor 16 includes means for computing a weighting factor for minimizing clutter-associated variance in the weighted combination of the first and the second sets of radiance data | Baum Eric (Rancho Palos Verdes, CA) | TRW Inc. (Redondo Beach, CA) | 03.01.1997 | 08.09.1998 | G06T5/50, G01S007/28, G01S013/50, G01S013/534, G06T5/50 | 08/794173 |
| 84 | 5793326 | Methods of generating a clutter threshold and arrangements for executing the methods | A method and arrangement for generating a clutter threshold by means of a CFAR circuit. In the process the partial registers of the CFAR are subdivided into storage blocks each containing a plurality of cell, and a block sum is formed from the sample values stored in each storage block. To form the clutter threshold for a signal under test, the individual block sums are compared in pairs according to a predetermined scheme, during which the greater block sum is determined. From these resulting greater sums, the smallest block sum (minimum) is selected and, from this, the clutter threshold is determined with a predetermined weighing. According to an alternative method, the block sums are sorted according to threshold is determined from this selected sum after a predetermined weighing | Hofele Franz Xaver (Donzdorf, DE) | Daimler-Benz Aerospace AG (Ulm, DE) | 10.01.1997 | 11.08.1998 | G01S7/292, G01S007/292, G01S007/34, G01S7/2927 | 08/802162 |
| 85 | 5781149 | Doppler radar clutter spike rejector | The invention is an improved clutter suppressor for MTI and pulse doppler radars operating so that the received clutter pulses are large enough to hard limit within the receiving system. It is especially useful for radars that use antenna beam scanning to perform tasks such as search, surveillance, and height finding because the combination of hard limiting with beam movement creates strong clutter residue at the output of a doppler filter. The invention can be implemented with either analog or digital technology, or with a digital processor and software | Long Maurice W. (Atlanta, GA), Family ID | --- | 13.05.1997 | 14.07.1998 | G01S13/524, G01S13/00, G01S013/534, G01S13/5246 | 08/855278 |
| 86 | 5760887 | Multi-pulse, multi-return, modal range processing for clutter rejection | A laser rangefinding system (12) that utilizes multiple pulse, multiple return, modal range processing for clutter rejection. A laser source (16) emits a series of laser beam pulses (42), and each reflected return from objects (46) in a scene for each of the pulses is recorded. Each return signal above a predetermined threshold is added as a count to a count table within a selected bin representing the range of the return signal. After all of the analog return signals are recorded, the range bin with the most counts is selected as the range of a target | Fink David (Los Angeles, CA), Halmos Maurice (Van Nuys, CA), Goran Dave (Los Angeles, CA) | Hughes Electronics (Los Angeles, CA) | 30.04.1996 | 02.06.1998 | G01S7/487, G01S7/48, G01S7/497, G01S7/481, G01C003/08, G01S7/487, G01S17/10, G01S7/481, G01S7/497 | 08/641255 |
| 87 | 5760734 | Radar clutter removal by matrix processing | An apparatus and method for radar detection of spectral moments and other spectral characteristics of echoes includes an agile antenna which directs an antenna beam in a direction for a dwell interval. A clutter filter stabilize the clutter filter, the clutter filtering is accomplished by matrix multiplication of the echo signal in each range bin by the inverse of the covariance matrix for that range. This reduces the dwell at each range interval, and provides a stream of pulse-to-pulse information at each range interval. The pulse-to-pulse data in each range interval is spectrum analyzed to extract the desired spectral information, which is displayed | Urkowitz Harry (Philadelphia, PA) | Lockheed Martin Corp. (Moorestown, NJ) | 18.11.1996 | 02.06.1998 | G01S13/42, G01S13/522, G01S13/00, G01S7/41, G01S7/02, G01S13/02, G01S013/522, G01S7/414, G01S13/426, G01S13/522, G01S2013/0245, G01S2013/0272 | 08/749609 |
| 88 | 5748140 | System for tracking radar targets in background clutter | A radar tracking system 100 adapted for use with existing radar tracking systems. The inventive system includes a radar target detection system 106, 108 for detecting radar targets in clutter using magnitude and angular position information obtained from return signals. A tracking algorithm 104 is used to track and update the positions of said targets with respect to the position of the radar system. The tracking algorithm includes a true target angle estimator 110 for maintaining accurate target angle information when the target is clutter and when the target is out of clutter. The tracking algorithm maintains accurate target distance information when the target is in clutter and when the target is out of clutter. In a specific embodiment, accurate distance information is maintained in a track file 122 where the amplitudes of return signals are stored once a target is detected by the detection system 100 | Schober Michael B. (Tucson, AZ) | Hughes Electronics (Los Angeles, CA) | 28.03.1996 | 05.05.1998 | G01S13/00, G01S13/72, G01S13/52, G01S013/72, G01S13/726, G01S13/52 | 08/627813 |
| 89 | 5694342 | Method for detecting signals in non-Gaussian background clutter | The invention provides a method for detecting signals in non-Gaussian background clutter, comprising the steps of:1) filtering input data to partition Gaussian input data from non-Gaussian input data: 2) estimating the intensity level of the Gaussian input data: 3) determining the probability distributions of the non-Gaussian input data: 4) determining the background noise level of the input data: 5) estimating noise parameters of the input data: 6) estimating the residual intensity of the input data using the noise parameters: 7) determining a detection statistic M from the input data, estimated noise parameters, and the residual intensity of the input data: 8) determining a standard deviation N.sub.i of the detection statistic, M.sub.i : 9) determining a normalized detection statistic Si, where S.sub.i =M.sub.i /N.sub.i,: 10) determining a maximum value, S.sub.imax of S.sub.i : 11) determining a mean value S.sub.Mean and standard deviation S.sub.Std dev of all S.sub.i excluding S.sub.imax : 12) determining a threshold .tau..sub..alpha. of a zero mean unit variance normal distribution corresponding to a predetermined false alarm probability, where .alpha. is a predetermined false alarm probability: and 13) generating an output signal if [S.sub.i -S.sub.Mean ]/S.sub.Std dev .gtoreq..tau..sub..alpha.. The invention may also be implemented as a program storage device readable by a machine which tangibly embodies a program of instructions executable by the machine to perform the above-referenced method steps | Stein David W. J. (San Diego, CA) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 24.10.1996 | 02.12.1997 | G01S7/292, G01S7/295, H03M001/08, H04B001/10, G01S7/2922, G01S7/295 | 08/742413 |
| 90 | 5686919 | Process for generating wind profiler data free of fixed ground clutter contamination | This invention discloses a process for generating wind profiler data which is free of fixed ground clutter contamination. The fixed ground clutter contamination is removed based upon the different decorrelation times of noise, clear air signals, and clutter. A nonlinear regression is used estimate the clutter content of the radar return which is then subtracted from the time series. This process is capable of removing broadband clutter from the desired clear air signal even though both may occupy the same Doppler frequency | Jordan James R. (Boulder, CO), Chadwick Russell B. (Boulder, CO), Family ID | --- | 06.06.1995 | 11.11.1997 | G01S13/95, G01S13/58, G01S13/00, G01S013/95, G01S13/581, G01S13/951 | 08/470546 |
| 91 | 5602760 | Image-based detection and tracking system and processing method employing clutter measurements and signal-to-clutter ratios | A method for measuring and quantifying clutter, and target detection and tracking systems that employs wavelet-based clutter quantification to generate a clutter number and a signal-to-clutter ratio derived therefrom to achieve improved target detection performance. The method processes video signals representative of an image scene containing a target and background clutter to provide for more accurate tracking of the target by a tracker(s). The method comprises processing the video signals to compute a wavelet clutter number, processing the video signals to compute a signal-to clutter ratio using the wavelet clutter number, and generating a pointer to a lookup table that sets parameters and selects the tracker that is to be used to track the target based upon the computed signal-to clutter ratio | Chacon Kim M. (Arcadia, CA), Groves Gillian K. (Lawndale, CA), Prager Kenneth E. (Los Angeles, CA) | Hughes Electronics (Los Angeles, CA) | 02.02.1994 | 11.02.1997 | G01S3/78, G01S3/786, G06T5/00, G01S007/00, G01S3/7864, G06K9/3241, G06T5/001 | 08/190827 |
| 92 | 5594450 | Radar system and method for detecting targets clutter using target intensity and angular position | A radar system includes a radar receiver that provides the amplitude and the angular position of a plurality of return signals. A computer forms a test function of amplitudes and angular positions of the plurality of return signals and compares the test function with a threshold value. Returns associated with a test function whose value is equal to or greater than the threshold value are determined to be targets, and those with lesser values are considered clutter | Schober Michael B. (Tucson, AZ), Family ID | --- | 07.06.1995 | 14.01.1997 | G01S7/292, G01S13/524, G01S13/00, G01S13/42, G01S013/534, G01S7/2927, G01S13/42, G01S13/5242 | 08/485743 |
| 93 | 5563604 | Weather radar using spectral gaussian envelope discrimination for clutter rejection | A method for removing clutter related frequency components from power spectrums generated from weather radar return signals to provide improved windshear detection capability. Weather radar return signals are synchronously detected and digitized to provide i and q time domain sample sequences. The i and q time domain sample sequences are passed through a window function and then transformed to frequency domain sequences by a Fast Fourier Transform. A power spectrum is generated from the frequency domain sequences. The spectrum is subjected to a Spectral Gaussian Envelope Discrimination (SGED) process in which the spectral envelope is scanned to identify any lobe therein having a slope greater than a predetermined minimum. A first pseudo-Gaussian sigma, calculated from the width and maximum amplitude of any such lobe, is compared with a second pseudo-Gaussian sigma, calculated from known conditions. If the first sigma is less than the second sigma, the lobe is deemed to be clutter related and is edited from the spectral envelope | Brandao Ruy L. (Ft. Lauderdale, FL), Manseur Arezki (Boca Raton, FL), Spires Randall C. (Boca Raton, FL), Weist William C. (Boca Raton, FL), Hermann Philip R. (Coral Springs, FL) | AlliedSignal Inc. (Morris Township, NJ) | 08.02.1995 | 08.10.1996 | G01S13/00, G01S13/95, G01S13/58, G01S13/524, G01S7/288, G01S7/292, G01S7/285, G01S007/292, G01S013/95, G01S13/951, G01S7/292, G01S13/524, G01S13/585, G01S2007/2883, G01S2007/2886 | 08/385494 |
| 94 | 5546084 | Synthetic aperture radar clutter reduction system | A method, and corresponding apparatus, for deriving clutter-reduced images of the ocean surface in synthetic aperture radar (SAR) systems. An estimate of ocean surface parameters is first made and subsequently updated iteratively, to provide a reliable model of a selected patch of the ocean as it existed when a series of conventional spotlight mode SAR images were obtained. Based on the estimated ocean model, and on models of ocean wave behavior, of radar scattering behavior, and of the SAR acquisition system, predicted SAR images can be generated, and compared with the measured SAR images, and clutter-reduced images can be produced as a result. In addition to the clutter-reduced images, the method and apparatus of the invention produce an accurate estimate of ocean surface data, and can be used in a reliable approach for detecting hard targets on the ocean | Hindman Carlton L. (Rancho Palos Verdes, CA) | TRW Inc. (Redondo Beach, CA) | 17.07.1992 | 13.08.1996 | G01S13/90, G01S7/02, G01S13/00, G01S7/41, G01S013/90, G01S7/411, G01S13/9035, G01S2013/9052 | 07/917632 |
| 95 | 5539412 | Radar system with adaptive clutter suppression | A method of spectral estimation of a received radar signal wherein an image of the received radar signal is applied to windows of differing prolate spheroidal sequences to calculate multiple eigenspectra. The value of each of said sequences are multiplied with the radar signal, and the Fourier transforms of the products provide a plurality of realizations of orthogonal eigenspectra. The orthogonal eigenspectra are combined into a minimum variance, low bias estimate of the mean power spectrum and an estimate of a variance of said spectrum for each frequency in the spectrum to provide a more accurate estimate of back ground noise and to further improve detection performance | Mendelson Howard B. (Columbia, MD) | Litton Systems, Inc. (Woodland Hills, CA) | 29.04.1994 | 23.07.1996 | G01S13/00, G01R23/16, G01S13/524, G01S7/288, G01S7/285, G01S013/00, G01R023/16, G01R23/16, G01S13/5244, G01S2007/2883 | 08/235391 |
| 96 | 5515060 | Clutter suppression for thinned array with phase only nulling | An active array antenna for use, for example, in a radar system, includes elemental antennas, each with a T/R module, distributed over a circular aperture. For lowest cost, the aperture is thinned. The T/R modules are operated at maximum output, to achieve maximum DC-to-RF efficiency, and for simplicity. A phase controller controls the phase shift which is imparted by each module to its signal, to form a main beam and its associated sidelobes. A perturbation phase generator portion of a phase controller adds a perturbation phase shift selected, in conjunction with a particular thinning distribution, to form a relatively wide null in the sidelobe structure, in which signal transduction is reduced. In a radar context, this null may be placed on a source of ground clutter or a jammer | Hussain Moayyed A. (Menands, NY), Yu Kai-Bor (Schenectady, NY), Bae Koeunyi (Ithaca, NY) | Martin Marietta Corp. (Moorestown, NJ) | 11.05.1995 | 07.05.1996 | H01Q3/00, H01Q3/46, H01Q21/22, H01Q003/00, H01Q3/46, H01Q21/22 | 08/439541 |
| 97 | 5502444 | Method and apparatus for improving the signal-to-clutter ratio of an airborne earth penetrating radar | The method improves the signal-to-clutter ratio of an airborne earth penetrating radar for distinguishing subsurface objects from surface clutter or above-ground objects. The method relies on the dispersive response of the signals returned from an subsurface object to distinguish these subsurface signals from the non-dispersive response signals returned by surface clutter. The electromagnetic response from a subsurface object is spread out over time in comparison to the response from surface clutter. A correlation coincidence detection methodology discriminates surface clutter based on the temporal persistence of a subsurface object. The correlation procedure produces a sequence of values which are used as the basis for detection. If the radar pulses detect a subsurface object, the sequence of values persists beyond the interval of integration containing the clutter response | Kohlberg Ira (Alexandria, VA) | Mandex, Inc. (Springfield, VA) | 23.09.1994 | 26.03.1996 | G01S7/32, G01S7/292, G01S7/285, G01V3/15, G01V3/17, G01S13/00, G01S13/88, G01S013/00, G01S7/292, G01S7/32, G01V3/17, G01S13/88 | 08/311674 |
| 98 | 5499195 | Fine-grained multi-planar clutter rejection processor | A fine grained multi-planar clutter rejection processor (10) for correlating multiple sets of data. The processor (10) maps each set of data onto a plurality of arrays (28-34). The data includes target data which is correlated between sets and clutter which is uncorrelated between sets of data. The system also includes a means for shifting (40) the positions of the second and subsequent arrays in a pattern which is larger for each successive array. In addition, a correlation identification unit (78) identifies the coordinate locations in the first array (28) which contain data points and which also contain data points in subsequent arrays in their shifted positions. In this way, data points identified in this manner are correlated and the remaining data points can be discarded as clutter. The processor (10) system is able to handle a very large number of data points per scan (over 100,000) over a high number of scans (such as eight). Due to its highly parallel approach, the total processing time is completely independent of the number of data points or scans | Castelaz Patrick F. (Yorba Linda, CA) | Hughes Aircraft Company (Los Angeles, CA) | 19.04.1994 | 12.03.1996 | G01S13/52, G01S7/41, G01S13/00, G01S7/02, G01S15/52, G01S15/00, G01S13/66, G01S013/52, G01S7/414, G01S13/52, G01S7/415, G01S13/66, G01S15/52 | 08/230041 |
| 99 | 5483240 | Radar terrain bounce jamming detection using ground clutter tracking | A radar jamming detection system is suitable for recognizing and distinguishing the presence of jamming and, particularly, terrain bounce jamming. The radar system includes a transmitter and a receiver. The receiver receives true radar skin return signals, in addition to ground clutter signals and jamming signals. The true radar skin return signals and ground clutter signals are recognizable in accordance with a predetermined receiver passband. Estimated target location, velocity and frequency data, as provided by a cueing radar, is used to set up the receiver passband for the radar detection system. Ground clutter range and angle measurements are used to determine an estimated ground range at the jammer angle, which is then compared with the cue range to determine if the received signals are terrain bounce jamming signals | Hsu Yuan S. (Rolling Hills Est., CA), Laquer Andy G. (Tustin, CA) | Rockwell International Corporation (Seal Beach, CA) | 28.09.1994 | 09.01.1996 | G01S13/00, F41G7/22, F41G7/20, G01S13/524, G01S13/53, G01S13/66, G01S7/02, G01S7/36, G01S7/292, G01S7/285, G01S13/44, G01S13/87, G01S007/36, F41G7/224, G01S7/024, G01S7/285, G01S7/292, G01S7/36, G01S13/5244, G01S13/53, G01S13/66, H04K3/22, H04K3/825, G01S13/4418, G01S13/87 | 08/314028 |
| 100 | 5451961 | Time varying adaptive clutter filter and clutter residue sensor | Clutter reduction is accomplished by dividing the sampling times of received radar signals into blocks containing a plurality of sampling times. The average clutter value in each block is estimated by averaging the signal returns for the sampling times in the block. Block average clutter values are time positioned at a selected sampling time position in a block and a smooth function with continuous first and second derivatives is passed through the average clutter value points. In a preferred polynomial segments between average clutter value points. Clutter values at the sampling points are extracted from the smooth function and respectively subtracted from the received radar signals. A clutter sensor examines the resulting radar signals for clutter distortion and eliminates radar signals that are not substantially clutter free | Rubin William L. (Whitestone, NY), Owenburg Jeffrey J. (Bethpage, NY) | Unisys Corporation (Blue Bell, PA) | 08.11.1993 | 19.09.1995 | G01S13/524, G01S13/95, G01S13/00, G01S7/292, G01S007/292, G01S013/95, G01S7/2923, G01S13/5244, G01S13/951 | 08/148447 |
| 101 | 5357256 | Radar receiver with adaptive clutter threshold reference | A method of detecting a target signal at a target signal level below the level of clutter in the return signals of a radar receiver. The receiver i.f. signals are correlated by multiplying delayed i.f. signals with undelayed i.f. signals. The correlated signals are filtered and then decomposed into their spectral component frequencies. The spectral components are compared, in turn, with individual thresholds. The individual thresholds are formed by summing the weighted values of selected ones of the spectral components, the selection being such that the spectral component being compared with a threshold is not used in forming that threshold. A target output signal is generated whenever any one of the spectral components exceeds the level of the threshold against which it is compared. In a second embodiment, in-phase and quadrature correlator signals are formed by the use of two correlators and two delay lines having different delay times that provide a 90 degree phase difference. The complex correlated signals are filtered, decomposed into spectral component frequencies and processed as in the first embodiment to generate a target output signal. In both embodiments, decomposition of the correlated signals may be carried out by means of a Discrete Fourier Transform | Peperone Salvador J. (Columbia, MD) | AlliedSignal Inc. (Morris Township, Morris County, NJ) | 17.08.1993 | 18.10.1994 | G01S13/00, G01S13/526, G01S013/526, G01S13/526 | 08/108201 |
| 102 | 5351056 | Target tracking in clutter degraded scenes using central level stereo processing | A computer method is disclosed for extracting data on a target from a clutter degraded environment by using non-time-synchronized results from two sensors stations. The method, which is employed in satellite tracking systems, transforming multiple non-synchronous sensor returns comprised of angles from line of sight observations from passive sensors into target position coordinates. Observations from successive returns of each sensor are paired and a triangulation point is calculated. Successive triangulation points are used to determine points on the projected trajectory of the target. These calculated target position coordinates may then used to project the future path of the target | Sawyer Joseph C. (Boulder, CO) | International Business Machines Corp. (Armonk, NY) | 21.06.1993 | 27.09.1994 | G01S5/02, G01S005/02, G01S005/12, H04B007/185, G01S5/02 | 08/080800 |
| 103 | 5345242 | Clutter rejection using connectivity | In a FLIR target detection system, true targets (52) are isolated from potential false target indications produced by background clutter through the use of a connectivity algorithm which attempts to find around each potential target (52) a closed path (65) of lower (or higher) intensity without exceeding a predetermined distance from the centroid (64) of the potential target. If the attempt is successful, the potential target (52) is a true target: if not, it is clutter | Roberts Gregory A. (Costa Mesa, CA), Voelz Lawrence D. (Irvine, CA), Gardemal, Jr. Robert C. (Irvine, CA) | Loral Aerospace Corp. (New York, NY) | 27.09.1990 | 06.09.1994 | G01S3/781, G01S3/78, G06K9/40, G06T5/00, G01S013/53, G01S3/781, G06K9/40, G06T2207/10048, G06T2207/30212 | 07/588776 |
| 104 | 5341808 | Doppler ultrasound clutter and sensitivity phantom | A clutter and sensitivity phantom for calibrating an acoustic beam generating clinical Doppler ultrasound instrument, comprising:a fluid-filled tank into which the ultrasound instrument probe is immersed: first and second sound scattering belts: an acoustic beam splitter intermediate the ultrasound probe and the first and second sound scattering belts, the acoustic beam splitter being oriented at a predetermined angle relative to the ultrasound instrument and to respective ones of the first and second signal scattering belts for splitting and directing the acoustic beam generated by the ultrasound instrument so as to be reflected off both of the first and second sound scattering belts at an identical angle, whereby portions of the acoustic beam reflected off of the first and second sound scattering belts may be separately or simultaneously monitored | Rickey Daniel W. (London, CA), Fenster Aaron (London, CA) | University Hospital (London), Development Corporation (Ontario, CA) | 27.05.1993 | 30.08.1994 | G01H3/00, G01S7/52, A61B008/00, G01H3/005, G01S7/5205 | 08/067995 |
| 105 | 5327141 | Clutter removal by polynomial compensation | Apparatus and method for removing unwanted components of a signal received from a radar transmitter. The unwanted components lie in a clutter Doppler frequency band. Such components are removed by first sampling the received signal at a rate sufficient to cause components of the received signal in the clutter Doppler frequency band to be validly sampled and components of the received signal in a desired target Doppler frequency band to be invalidly sampled. A signal equivalent to the values of a polynomial fit to this sampled signal then provides an estimate of the unwanted clutter components. This estimate is subtracted from the original received signal to provide a signal with the unwanted clutter components removed. A significant improvement in receiver sensitivity as well as a reduction in dynamic range requirements of a post detection digital signal processor is achieved through the use of this invention | Sheldon Edward J. (Lexington, MA) | Raytheon Company (Lexington, MA) | 06.11.1986 | 05.07.1994 | G01S13/00, G01S13/524, G01S013/534, G01S13/524 | 06/927612 |
| 106 | 5311188 | Radar apparatus provided with a coherent clutter map | A radar apparatus provided with transmitter means (1), rotating antenna means (2) and receiver means (3) for the transmission per burst and the processing in a video processor of radar echo signals. The video processor includes moving target detection unit (4) provided with a doppler filter bank, for instance an FFT processor, and slow moving target detection unit (6), provided with coherent clutter maps, one map for each radar transmitter frequency used. The coherent clutter maps are also used for reducing the clutter strength of radar echo signals which are applied to the moving target detection unit (4), by subtracting the coherent clutter strengths stored in the clutter maps from the radar echo signals | Meijer Wietze J. H. (Enschede, NL), Nooy Petrus N. C. (Hengelo, NL) | Hollandse Signaalapparaten B.V. (Hengelo, NL) | 16.12.1992 | 10.05.1994 | G01S13/00, G01S13/524, G01S013/50, G01S13/5248 | 07/991588 |
| 107 | 5299174 | Automatic clutter elimination | An apparatus and method for clutter elimination from signals which digitizes a signal to generate n samples of the signals. M basis functions (such as various levels of filters) are fit to the n samples. An i+1 basis function of the m basis functions is iteratively subtracted from each of the n samples, and the difference is stored in an i difference signal until the i+1 difference signal is less than a threshold. In various embodiments, the threshold may be an absolute noise floor (R.sub.O.sup.min) preset by a manufacturer or a user. In other embodiments, the threshold may be based upon an absolute or relative predictor error of the signal once the basis function (filter) has been removed. The i difference signal may be used for performing a frequency estimate of the signal | Forestieri Steven F. (Santa Clara, CA), Spratt Ray S. (San Jose, CA) | Diasonics, Inc. (Milpitas, CA) | 26.01.1993 | 29.03.1994 | G01S15/58, G01S15/89, G01S15/00, G06F17/17, G03B042/06, G01S15/58, G01S15/8981, G06F17/17 | 08/009279 |
| 108 | 5249578 | Ultrasound imaging system using finite impulse response digital clutter filter with forward and reverse coefficients | An asymmetric finite impulse response digital filter, typically used in an ultrasound imaging system, includes forward and reverse sections. In the forward section, a group of input data samples is multiplied by a set of results. The first intermediate results are summed to provide a first output sample. In the reverse section, the group of input data samples is the forward section to provide second intermediate results. The second intermediate results are summed to provide a second output sample. The process is repeated to provide multiple first and second output samples. A signal estimation unit estimates a characteristic of the input data samples, such as the frequency of a Doppler ultrasound signal, based on the first and second output samples. The filter provides twice as many output samples as prior art filters for a given set of input data samples. The filter is preferably used as a clutter filter to remove low frequency clutter from a Doppler ultrasound signal | Karp Sydney M. (Reading, MA), Beaudin Raymond A. (Windham, NH) | Hewlett-Packard Company (Palo Alto, CA) | 15.09.1992 | 05.10.1993 | G01S15/89, G01S15/00, G01S7/52, H03H17/06, A61B008/00, G01S7/52026, G01S15/8979, H03H17/06 | 07/945313 |
| 109 | 5243987 | Apparatus for obtaining blood backscattering power excluding clutter components | An apparatus for obtaining a blood backscattering power, comprising a signal input unit for inputting an electric signal which is converted from an ultrasound signal which has been generated in a certain depth in the human body by reflecting or backscattering: a Doppler spectrum obtaining unit for obtaining a Doppler spectrum which contains information on a distribution of an intensity of the above electric signal as a function of a time and a Doppler frequency, where the Doppler frequency is a quantity indicating a velocity component in a direction of the above transmitted ultrasound signal, of an object which backscatters the transmitted ultrasound signal: a Doppler frequency range determining unit for determining an elimination frequency range of the above Doppler frequency for each time: and an accumulating unit for accumulating the above intensity over a whole range of the above Doppler frequency except the above elimination frequency range for each time, to obtain a blood backscattering power of the time. The apparatus may further contain:a time range determining unit for determining an efective time range: and an averaging unit for averaging the above blood backscattering power over the efective time range to obtain an average of the above blood backscattering power in the efective time range | Shiba Akira (Kawasaki, JP) | Fujitsu Limited (Kawasaki, JP) | 27.09.1991 | 14.09.1993 | G01N29/02, G01F1/66, G01N29/032, A61B008/00, G01F1/663, G01N29/02, G01N29/032, G01N2291/02836, G01N2291/101 | 07/766090 |
| 110 | 5228009 | Parametric clutter elimination | Signal processing apparatus and methods for elimination of undesirable clutter signals from desirable signals. This is performed without the use of filters by subtracting orthonormal basis functions from signal samples until the appropriate degree of clutter removal is achieved. Estimates of frequency information such as Doppler shifts due to fluid flow may thus be achieved with superior discrimination of true flow signals from sources of clutter or artifact, greater sensitivity to low flow rates, minimal computational effort and with fewer samples than the prior art | Forestieri Steven F. (Santa Clara, CA), Spratt Ray S. (San Jose, CA) | Diasonics, Inc. (Milpitas, CA) | 10.04.1992 | 13.07.1993 | G01S15/58, G01S15/89, G01S15/00, G06F17/17, G03B042/06, G01S15/58, G01S15/8981, G06F17/17 | 07/867038 |
| 111 | 5101210 | Signal dynamic range compression apparatus and method including clutter estimation and reduction | The maximum amplitude of an input signal (IN) is compressed or reduced to a smaller value suitable for operation on the compressed signal (OUT) by a downstream signal processing stage (16) having insufficient dynamic range, ratio of maximum amplitude to root-mean-square (RMS) noise, to accommodate the original input signal (IN). The input signal (IN) is digitally sampled with coarse resolution to generate a correction signal (44) having a waveform which approximates only the large signal components (24) of the input signal (IN). Where the input signal (IN) consists of recurring received radar pulses, the large signals (24) represent clutter. The amplitude of the correction signal (44) is lower than and increases as a predetermined function of the amplitude of the input signal (IN), and is subtracted from the input signal (IN) so that the large signal components (24) are reduced whereas the small signal components (26), which represent desired target information, retain their original amplitude. Time and/or space estimates of the large signals may be stored and updated, and combined with the sampled input to generate the correction signal (44). A threshold is provided such that only input signals have a predetermined maximum amplitude are compressed | Milan John M. (Canoga Park, CA) | ITT Corporation (New York, NY) | 21.12.1990 | 31.03.1992 | G01S7/285, G01S7/34, G01S007/34, G01S7/34 | 07/632152 |
| 112 | 5061934 | Hybrid clutter cancellation method and system for improved radar performance | A system is disclosed for use with radar systems so as to reduce the dynamic range requirement of the analog to digital converter through analog clutter cancellation prior to digitization. Clutter return estimates are formulated via modern digital signal processing techniques, converted to analog representation, and subtracted from the received waveform. Typically, the MTI cancellation is performed on the quadrature components of the received signal. The complex residue is then processed for target detection. This quadrature processing is not illustrated in the figures. In practice, sampling the received waveform prior to baseband down conversion, at an intermediate frequency, is also feasible. Digital synchronous detection and coherent MTI processing are then implemented in the digital signal processor. Rather than employ a radar signal processor which is either all analog or all digital it is beneficial to utilize hybrid schemes which capitalize on the advantages of both. A hybrid system is disclosed in which the acoustic delay line, which fundamentally limits analog MTI canceller performance, is replaced by a digital delay line. In effect, the transmitter crystal, delay medium, and receiver crystal are replaced by the analog to digital converter, digital delay, and digital to analog converter. The hybrid clutter canceller with digital processor and analog waveform synthesizer utilizes modern signal processing techniques to estimate the clutter return which is subtracted from the incoming analog signal. The full dynamic range of the received signal is not presented to the analog to digital converter, reducing the number of bits required for target detection in clutter. In effect, application of the hybrid clutter canceller reduces the A/D converter probability of saturation for a given A/D converter | Brown Russell D. (Holland Patent, NY), Weiner Donald D. (Fayetteville, NY), Wicks Michael C. (Utica, NY) | The United States of America as represented by the Secretary of the Air (Washington, DC) | 09.11.1990 | 29.10.1991 | G01S13/524, G01S13/00, G06K9/32, G01S013/534, G01S007/295, G01S13/5244, G06K9/3241 | 07/611217 |
| 113 | 5025143 | Enhanced clutter suppression apparatus for use with an infrared search and surveillance system | A clutter suppressor/target locator apparatus is configured to manipulate rget video data on a particular channel according to a predetermined algorithm, so as to selectively emphasize those area of a scene containing targets of appreciable contrast to the background and de-emphasize those areas where the brightness levels change gradually from point to point. The algorithm takes into account points ahead and behind the point or picture element being tested, and also equal points or adjacent channels. The apparatus is substantially free of false alarms, and the unique configuration thereof allows detection of the presence of a target on an extremely rapid basis | Dayhoff Edward S. (Silver Spring, MD) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 06.07.1982 | 18.06.1991 | G01S17/02, G01S17/89, G01S7/487, G01S17/00, G01S7/48, H04N5/33, H04N005/21, G01S7/487, G01S17/023, G01S17/89, H04N5/33 | 06/395223 |
| 114 | 4996437 | Optical clutter scene simulator | An optical clutter scene stimulator generates a scene simulating atmospheric optical clutter produced by a nuclear event. The stimulator focuses a display source scene on a focal plane, then displaces the scene from the focal plane so as to provide a scene representing optical clutter. Alternately, the optical clutter scene can be generated by performing an optical Fourier transform | Hendrick, Jr. Roy W. (Goleta, CA) | Mission Research Corporation (Santa Barbara, CA) | 25.10.1988 | 26.02.1991 | G01S3/78, G01S3/781, G01D018/00, G01S3/781 | 07/262510 |
| 115 | 4977405 | Programmable if clutter canceller | An IF Clutter Canceller using delay lines and acoustic charge transport (ACT) devices to subtract one interpulse period from another interpulse period. The first interpulse period is time demultiplexed with a tapped delay line and stored in ACT devices. The second interpulse period is time demultiplexed through the same delay line as was the first interpulse period. The stored time segments of the first interpulse period are released from the ACT devices and subtracted from the time demultiplexed time segments of the second interpulse period. The resulting clutter cancelled time segments are then assembled into a clutter cancelled interpulse period with a second tapped delay line | Nothnick Carl E. (Pasadena, MD) | Westinghouse Elecric Corp. (Pittsburgh, PA) | 25.01.1990 | 11.12.1990 | G01S13/00, G01S13/534, G01S013/538, G01S13/534 | 07/469971 |
| 116 | 4972194 | Method and device for compensating for the speed of clutter in a coherent doppler radar with variable blind speed | .phi.r.sub.i from one period to the next and which is due to clutter in a given range cell. Then, this phase variation .phi.r.sub.i is memorized and is used during the course of each of the periods of repetition of the next burst to modify the phase of the signal received from the clutter from the same range cell in a maner as to displace its Doppler frequency towards the zero frequencies band, and band which corresponds to the rejection zone of the fixed echoes eliminating filter | Carrara Bruno (Paris, FR), Guillerot Jean-Claude (Versailles, FR), Joncour Hubert (Palaiseau, FR), Drevet Jacques (Paris, FR) | Thomson-CSF (Paris, FR) | 03.10.1988 | 20.11.1990 | G01S13/00, G01S13/524, G01S13/22, G01S007/28, G01S13/227, G01S13/524 | 07/253108 |
| 117 | 4965585 | Device for moving-clutter elimination in a radar | The invention resides in the fact that the moving-clutter elimination filter is composed of several transversal filters whose n+1 multiplying coefficients K0, K1, . . . , K.alpha., . . . , Kn are fixed and are derived from the coefficients A0, A1, . . . , A.alpha., . . . , An of the fixed-clutter elimination filter by multiplying the latter by the factors | Lepere Guy (Le Mesnil Esnard, FR), Kunegel Jacques (Paris, FR), Coulmier Jean-Pol (Sevres, FR) | Thomson CSF (Paris, FR) | 08.03.1989 | 23.10.1990 | G01S13/00, G01S13/524, G01S013/526, G01S013/53, G01S13/524 | 07/321420 |
| 118 | 4940988 | Two parameter clutter map | A two-parameter clutter map for storing two variables for every spatial fluctuation characteristics of the interference from scan-to-scan. The two variables are obtained by processing input data from an integrator in two or their difference in logarithmic form is employed as a measure of the scan-to-scan fluctuation characteristics. An option to control alarms and the leading edge of moving rain storms is also provided | Taylor, Jr. John W. (Baltimore, MD) | Westinghouse Electric Corp. (Pittsburgh, PA) | 02.11.1988 | 10.07.1990 | G01S13/00, G01S13/524, G01S013/86, G01S13/5248 | 07/266192 |
| 119 | 4928131 | Sea clutter suppression radar | A sea clutter suppression radar is capable of effectively suppressing the reflected signal using RF waves of a single frequency by simultaneously sending the RF waves each having horizontal and vertical polarizations, and detecting, from a reflected signal from a target, horizontally and vertically polarized components and the vector sum and the vector difference signals between these components, and then processing these signals to suppress the reflected signal from the sea surface. The radar includes at least one antenna for simultaneously sending horizontally and vertically polarized RF waves, first and second detectors each for detecting intermediate frequency signals or horizontally and vertically polarized components of reflected RF waves, third and fourth detectors each for detecting IF signals of the vector sum and vector difference between the horizontally and vertically polarized components and a polar signal generator for generating a polar signal based upon the difference between the addition of both outputs of the first and second detectors, and the absolute value of the difference between said both outputs and the difference between the outputs of the third and fourth detectors | Onozawa Kazuo (Tokyo, JP) | Oki Electric Industry Co. (Tokyo, JP) | 07.09.1988 | 22.05.1990 | G01S7/02, G01S013/50, G01S7/024 | 07/241236 |
| 120 | 4910401 | LWIR sensor system with improved clutter rejection | The system comprises a scanning telescope for scanning a field of view in a vertical direction. A detector array is positioned in the focal plane of the telescope for receiving radiant energy from the scanned image. The detector array comprises a plurality of elements which are positioned such that adjacent elements along the scan direction are offset with respect to each other. A processor receives output signals from each of the elements. The processor delays the signals received from leading elements in the array and adds these delayed signals to output signals from trailing elements in the array to form pseudodetector sums. Pseudodetector sums formed in this manner are geometrically filtered in a cross-scan direction and also filtered in the along scan direction | Woods Weightstill W. (Redmond, WA) | The Boeing Company (Seattle, WA) | 20.01.1982 | 20.03.1990 | G02B23/00, G02B26/12, H04N5/33, H04N3/02, H04N3/09, H01L025/00, G02B026/10, H04N3/09, H04N5/33, G02B23/00, G02B26/12 | 06/341131 |
| 121 | 4907001 | Extraction of radar targets from clutter | The extraction of radar targets, in particular airplanes or cruise missiles, from clutter is typically based on the target's velocity relative to the ground. Equipment using this principle is usually referred to as a doppler processor or moving target indicator. In situations where severe clutter is encountered, as for example where a look-down radar is trying to find low-flying cruise missiles, extraction of the target solely through its velocity relative to the ground is generally unsatisfactory. A similarly situated human observer looking down can recognize a target both from its motion and the characteristic shape of a fuselage with wings. The principle of this "shape recognition" or "pattern recognition" is here applied to radar by utilizing the so-called radar signature of the target. The conventional small-relative-bandwidth radar which uses signals that are amplitude modulated onto a sinusoidal carrier does not yield enough of a radar signature for this application but the so-called "carrier-free radar" does. Carrier-free radar is also known as "impulse radar", "nonsinusoidal radar", or "large-relative-bandwidth radar" | Harmuth Henning F. (Potomac, MD) | Geophysical Survey Systems, Inc. (Hudson, NH) | 27.02.1989 | 06.03.1990 | G01S13/02, G01S13/00, G01S7/02, G01S7/41, G01S13/524, G06K9/00, G01S007/28, G01S7/412, G01S13/0209, G01S13/5246, G06K9/00201 | 07/316585 |
| 122 | 4890113 | Second time around clutter cancellation system | The present invention provides a system that cancels second time around clutter in a multiple pulse repetition frequency radar system which uses three groups of differently spaced pulses. The system processes returns from a clutter cancellation group of eight pulses from three different concatenated pulse repetition frequency groups, using two pulses from one group, all pulses from a central group and two pulses from a third group. The pulse returns are each multiplied by a different weight and the eight weighted returns are added together and output as the filtered return signal. As the weights of the outer pairs of pulses increase, as compared to the weights of the inner four pulses, the second time around clutter cancellation effects increase and the first time around clutter cancellation effects decrease | Jacomini Omar J. (Severna Park, MD) | Westinghouse Electric Corp. (Pittsburgh, PA) | 09.12.1987 | 26.12.1989 | G01S13/00, G01S13/528, G01S13/532, G01S013/54, G01S13/528, G01S13/532 | 07/130706 |
| 123 | 4829307 | Recursive radar clutter filter | A recursive radar filter arranged to provide filtering of ground clutter signals from radar echoes in the form of short batches of pulses. The filter includes a feed-forward section with delay, adder, and fixed amplifier elements. The filter also includes a feedback section which includes similar elements. Two time-varying amplifiers are included in the filter which change gain as the pulses are applied to the input of the filter. In a three delay version of the filter, the gain of one of the time-varying amplifiers is such that the feed-forward section of the filter does not pass any pulses until the fourth pulse has been applied to the filter. After the third pulse, the gain of this time-varying amplifier increases on each successive input pulse. In another embodiment, the two time-varying amplifiers are eliminated by making all of the fixed gain amplifiers time-varying in relationship with the interpulse period of the pulse input signal. Both arrangements allow recursive filtering without the need for extra pulses or pulse tapering to control transients in the filter | Jacomini Omar J. (Severna Park, MD) | Westinghouse Electric Corp. (Pittsburgh, PA) | 25.04.1985 | 09.05.1989 | G01S13/53, G01S13/00, H03H11/04, G01S013/50, G01S13/53, H03H11/04 | 06/727173 |
| 124 | 4811020 | Radar protected against rain clutter and method for protecting a radar against rain clutter | The radar is designed to identify and then eliminate rain clutter signals. For this, the radar works in circular polarization with alternately identical and opposite polarization directions at transmission and reception, from one recurrence to the next one. The signals are identified by a comparator which compares the sigma video signals relating to the same distance quanta for two successive recurrences, the identifying criterion being a major difference in the level of the signals compared, for rain clutter signals, and little difference for useful echo signals. A switch controlled by the comparator eliminates the parasite signals | Montheil Jean C. (Fontenay Sous Bois, FR) | Thomson-CSF (Paris, FR) | 27.04.1987 | 07.03.1989 | G01S7/02, G01S007/36, G01S7/025 | 07/042827 |
| 125 | 4804962 | Clutter elimination radar | A radar receiver having a clutter-elimination filter in the receiver's intermediate frequency stage. The filter is centered on the intermediate frequency f.sub.i and has a transfer function in which a band-pass characteristic is superimposed on a band-rejection characteristic. The band-pass response has a principal lobe substantially conforming to the function (sin x)/x with x=(w-w.sub.i).pi.T. The band-rejection response presents an attenuation zone centered about f.sub.i : this zone is wide enough to suppress much of the response from clutter but narrow enough to avoid suppressing much of the energy in the echo from the target. For example, the width of the attenuation zone may be from about f.sub.i -0.2/T to about f.sub.i +0.2/T. The filter provides a maximum response on each side of the attenuation zone, spaced from f.sub.i by about 0.4/T Hz in each direction. Outside the maxima, the response is dominated by the band-pass characteristic and achieves transmission minima at about 1/T Hz above and below f.sub.i. Examples are given of filters providing such transfer functions | Picquendar Jean-Edgar (Whitman, MA) | Diamond Devices, Inc. (Wareham, MA) | 04.08.1983 | 14.02.1989 | G01S13/522, G01S13/00, G01S7/292, H03H7/01, H03H7/06, G01S007/28, H03H007/12, G01S7/2921, G01S13/522, H03H7/06, H03H7/07, H03H7/1783 | 06/520205 |
| 126 | 4766435 | Adaptive radar for reducing background clutter | An adaptive radar apparatus is provided for substantially reducing background clutter, particularly relatively time-invariant clutter, such as sea clutter, and especially at low radar grazing angles. The apparatus includes a transmitting antenna having horizontally and vertically oriented, transmitting elements and a relative phase control therebetween and a receiving antenna also with horizontally and vertically oriented receiving elements also having relative phase detection and phase shift possible therebetween. A controllable radar signal generator is provided for supplying signals to the transmitting antenna and a controllable signal processor is provided for processing return signals from the receiving antenna. Means are included for determining, from return test signals, a background mean null polarization for a number of radar range and azimuth cells and for providing null polarization control signals H.sub.o, V.sub.o and .phi..sub.o, to the signal generator and return signal processor to cause the radar to operate at a polarization state which is the same as the clutter mean null polarization. A corresponding method is provided for reducing background clutter, especially relatively time-invariant sea clutter, a low grazing angle radar | Wells Donald R. (Villa Park, CA) | Hughes Aircraft Company (Los Angeles, CA) | 27.05.1986 | 23.08.1988 | G01S7/02, G01S007/42, G01S7/026 | 06/867866 |
| 127 | 4749994 | Signal processing for radars having clutter maps | Method for determining and using clutter estimates in a radar clutter map. The method does not require synchronization of the transmitted radar pulses with the azimuth coordinates of the map cells. Data inputs close to each map azimuth location are used to estimate the echo amplitude in the map cell which would result if the antenna beam was pointing directly at the clutter when one data sample occurred. A burst of pulses are transmitted and return echoes are processed to produce clutter signals at least twice within the time it takes for the antenna to scan one beamwidth. Clutter echoes received adjacent in azimuth to the map cell for which the value is being calculated are converted by a formula into a value for adjusting the present map cell value. The formula takes into consideration the magnitude of the values, the difference between the values, the antenna beam width, and the azimuth spacing of the samples. The map values are outputted for threshold level control by other techniques including the selection of the larger of the two stored cell values straddling the azimuth of the threshold controlled signal | Taylor, Jr. John W. (Baltimore, MD) | Westinghouse Electric Corp. (Pittsburgh, PA) | 04.06.1986 | 07.06.1988 | G01S13/00, G01S7/292, G01S13/524, G01S007/44, G01S7/2927, G01S13/5244, G01S13/5248 | 06/870583 |
| 128 | 4743910 | Frequency domain, pulse compression radar apparatus for eliminating clutter | Frequency domain, pulse compression CW radar apparatus comprises a frequency synthesizer which provides RF and IF CW signals and linear frequency modulator (LFM) which provides a saw tooth LFM ramp signal with the f.sub.LFM. A mixer combines the f.sub.LFM signal with the f.sub.RF signal to provide a CW radar signal having a frequency, (f.sub.RF +f.sub.LFM) for transmitting by a transmitter. A receiver receives time-delayed CW radar return signals reflected, for example, from clutter at a one range and from a target at another range. A second mixer down-converts the clutter and target return signals to an intermediate frequency for processing and a third mixer extracts the f.sub.LFM signal from the intermediate frequency clutter and target return signals to provide, in a frequency-time domain, rectangular wave, clutter and target signals. A time gate and a frequency notch filter are connected for receiving these rectangular wave signals, the notch filter having at least one frequency notch for filtering out the clutter signal while passing the target signal, assuming the frequency characteristics of the clutter and target signals are different from one another. A synchronization detector provides in phase (I) and quadrature (Q) components of the remaining target signal: an A/D converter and sampler digitizes and samples the I and Q signal components, the samples being sequentially processed in a FFT digital pulse compressor and in a FFT doppler processor to provide conventional range and doppler cell information | Hill Richard M. (La Habra, CA), Parton Richard D. (Fullerton, CA), Sawyers James H. (Santa Ana, CA) | Hughes Aircraft Company (Los Angeles, CA) | 16.12.1986 | 10.05.1988 | G01S13/00, G01S13/34, G01S13/58, G01S013/28, G01S13/343, G01S13/584 | 06/943275 |
| 129 | 4742353 | Digital processor for radar signals which can perform adaptive suppression of clutter means of a parametric estimator | A digital processor for radar signals which can perform adaptive suppression of the disturbance clutter and enhancement of the useful signal of given Doppler frequency. It can approximate the principle of operation of the optimum processor, which is that processor which maximizes the signal-to-noise ratio. Such processor can also cancel, in a adaptive manner, a clutter component having an approximately Gaussian power spectrum | D'Addio Egidio (Naples, IT), Farina Alfonso (Rome, IT) | Selenia Industrie Elettroniche Associate S.p.A. (Rome, IT) | 16.04.1987 | 03.05.1988 | G01S13/00, G01S7/292, G01S13/524, G01S013/86, G01S7/2923, G01S13/5244 | 07/039751 |
| 130 | 4719466 | Adaptive radar signal processor for the detection of useful echo and the cancellation of clutter | Adaptive radar signal processor apt to detect the useful echo in the presence of an additive disturbance made up of clutter and noise, through which the disturbance can be cancelled and the useful signal can be enhanced by means of the synthesis of a filter, adapted to the useful signal, which rejects the disturbance spectrum frequency components by adapting itself in real time to its variations | Farina Alfonso (Rome, IT), Studer Flavio A. (Rome, IT) | Selenia-Industrie Elettroniche Associate S.p.A. (Rome, IT) | 13.12.1984 | 12.01.1988 | G01S13/00, G01S13/524, G01S007/66, G01S13/5244 | 06/681497 |
| 131 | 4713664 | Point clutter threshold determination for radar systems | An adaptive detection threshold system for moving target detector and moving target indicator radar systems. The threshold system uses data from the echo input signal to reconstruct a threshold level closely resembling the output clutter residue in doppler filters due to point clutter sources. At least three azimuth data values are used, with the values being from adjacent coherent processing intervals and separated in azimuth a distance approximately equal to the beamwidth of the antenna system. The data at the same range from the three azimuths is combined to form an estimate of the residue at the output of a doppler filter, assuming that the echo is caused by point clutter. Compensation for radar instability and changes in scan rate or interpulse period is included. Data from conventional constant false alarm rate processing designed to control alarms from distributed interference, such as weather echoes, is also used to compensate the residue estimate | Taylor, Jr. John W. (Baltimore, MD) | Westinghouse Electric Corp. (Pittsburgh, PA) | 24.05.1985 | 15.12.1987 | G01S13/00, G01S13/524, G01S013/52, G01S13/5246, G01S13/5248 | 06/738126 |
| 132 | 4688044 | Multiple range interval clutter cancellation circuit | A multiple range interval clutter cancellation circuit for MTI radars is disclosed, for assuring cancellation of narrow band clutter in the second or further range interval, while preserving wideband cancellation in the nearer range intervals and economizing on the number of fill pulses. The circuit includes two clutter cancellers. One canceller has a relatively narrow band clutter rejection bandwidth, and effectively a higher number of fill pulses in relation to the clutter rejection bandwidth and effective number of fill pulses for the second canceller. The outputs of the two cancellers are subjected to an AND gate function, such that only targets which pass through the clutter rejection bandwidth of both cancellers are reported as a target. The circuit obtains the elimination of returns from ambiguous range interval clutter with less transmitted energy and time than conventional canceller circuits | O'Brien Edwin L. (Fullerton, CA) | Hughes Aircraft Company (Los Angeles, CA) | 07.07.1986 | 18.08.1987 | G01S13/53, G01S13/526, G01S13/00, G01S13/20, G01S013/52, G01S13/20, G01S13/526, G01S13/53 | 06/882582 |
| 133 | 4684950 | Methods of and circuits for suppressing doppler radar clutter | Clutter suppressors and methods of clutter suppression for radars which employ the doppler effect for enhancing signals due to moving targets relative to signals due to clutter caused by land, sea or rain. Specifically, the disclosure concerns suppressors and methods of clutter suppression for cw doppler, pulse doppler and MTI (moving target indication) radars. The suppressors reduce the occurrence of radar output due to clutter by permitting and prohibiting radar output on the basis of the strength of signals that contain doppler frequency components of the radar echo | Long Maurice W. (Atlanta, GA) | --- | 20.07.1984 | 04.08.1987 | G01S13/536, G01S13/00, G01S13/524, G01S013/52, G01S13/524, G01S13/5244, G01S13/5246, G01S13/536 | 06/633056 |
| 134 | 4644357 | Radar clutter simulator | The simulation of clutter echo return signals for a radar system is accomplished using two sets of diode noise sources, a frequency synthesizer for bandwidth control, multiplexing control, two D/A converters and mixers, a 90-degree sower splitter, and a summer: the output of the summer being the simulated clutter. The two sets of noise sources each produce a digital encoded controlled bandwidth Gaussian noise signal which is strobed by the multiplexing control unit firstly to the pulse repetition interval of the radar system and secondly to the data rate of the radar system. The two strobed D/A converters convert the two digital noise signals into their analog equivalents. The two separate video channels are required to obtain the Rayleigh noise distribution characteristic of clutter. This distribution results when the analog signals from the D/A converters are multiplied with in-phase and quadrature RF reference frequencies in the two mixers, then summed in the summer | Schaaf Gregory (Van Nuys, CA), Bircsak Garin S. (North Hollywood, CA) | The United States of America as represented by the Secretary of the Air (Washington, DC) | 04.09.1985 | 17.02.1987 | G01S7/40, G09B9/54, G01S007/40, G01S7/4052, G09B9/54 | 06/772581 |
| 135 | 4630052 | Suppressor of second-time-around clutter echoes for MTI pulse radar provided with power oscillator | A device for suppressing second-time-around echoes from far-out clutter in an MTI pulse radar lies in shunt with a digital signal processor connected to the receiver output of the radar whose transmitter includes a power oscillator maintaining phase coherence only for the duration of an oscillator is triggered for different pulse-repetition frequencies of predetermined values in alternate scanning intervals each lasting for an antenna rotation by half a beamwidth. Echoes from a group of radar pulses emitted in one interval are accumulated and then compared in magnitude with accumulated echoes from another such group emitted in an adjoining interval. If these magnitudes--relatively adjusted to compensate for the different numbers of pulses per group--are substantially equal over a sequence of antenna revolutions, they are classified as due to second-time-around clutter echoes and the output signal of the processor is eliminated for the corresponding scanning intervals | Galati Gaspare (Rome, IT), Giaccari Ennio (Rome, IT) | Selenia-Industrie Elettrotechniche Associate S.p.A. (Rome, IT) | 04.05.1984 | 16.12.1986 | G01S13/528, G01S13/00, G01S13/20, G01S007/28, G01S13/20, G01S13/528 | 06/607204 |
| 136 | 4628318 | Ground clutter suppression technique | A ground clutter suppression technique is disclosed utilizing two parallel return signal processing paths, both utilizing linear-to-logarithmic conversion capability and one having a signal delay capability for one pulse repetition. The outputs are subtracted and are subsequently compared with a factor related to the root-mean-square (rms) of two deviation inputs, one input functionally related to apparatus limitations and one deviation input functionally related to antenna position (step between samples) for each signal received. The Doppler frequency standard deviation inputs are then summed rms and used to select an amplitude standard deviation which is compared with the amplitude difference between successive return signals. Thereafter, the logic decision output is operated on utilizing a digital filter to essentially eliminate ground clutter or small variance (PRF to PRf) return signals from the display | Alitz Orville J. (Marion, IA) | Rockwell International Corporation (El Segundo, CA) | 02.12.1983 | 09.12.1986 | G01S13/95, G01S13/00, G01S13/524, G01S013/95, G01S13/5242, G01S13/951 | 06/557679 |
| 137 | 4625209 | Clutter generator for use in radar evaluation | The testing of radar systems is enhanced with the use of clutter generator that simulates realistic terrain echo returns which are provided in real-time. A fast array processor is used in combination with a Fourier Transform processor to produce a complex digital output having time, frequency and magnitude information corresponding to the composite echos from thousands of points. A digital-to-analog converter filters the output and a single-sideband mixer converts the digital output to a radio frequency signal | Lawrence Gene W. (Spokane, WA), Davis Thomas L. (Carrollton, TX) | The United States of America as represented by the Secretary of the Air (Washington, DC) | 26.06.1984 | 25.11.1986 | G01S7/40, G01S007/40, G01S7/4052 | 06/624846 |
| 138 | 4622555 | Coded pulse Doppler radar with clutter-adaptive modulation and method therefore | A coded pulse Doppler radar having apparatus for determining the separation between the frequency spectrum returned from clutter and the frequency spectrum returned from a desired target, and circuitry responsive to the apparatus for adjusting the code to maintain the separation at least at a predetermined minimum value | Doggett John G. (Scottsdale, AZ), Jones John M. (Mesa, AZ), Waddoups Ray O. (Mesa, AZ) | Motorola, Inc. (Schaumburg, IL) | 02.09.1982 | 11.11.1986 | G01S13/24, G01S13/532, G01S13/00, G01S13/524, G01S13/26, G01S013/26, G01S007/42, G01S13/24, G01S13/26, G01S13/5244, G01S13/532 | 06/414158 |
| 139 | 4586044 | Clutter positioning for electronically agile multi-beam radars | An electronically agile multi-beam radar including a clutter positioning system for positioning the band of clutter signals in the derived doppler frequency spectrum of each of the individual beams is disclosed. The radar is operative to switchedly transmit a plurality of beams directionally separated by time sharing the illuminating power thereof. Each beam includes at least one transmission of a plurality of R.F. pulses constituting a radar look. The radar is also operative to receive echo R.F. pulses of the look from each transmitted beam dispersed in time with echo R.F. pulses of the looks of the other transmitted beams of the plurality. The clutter positioning system operates to maintain substantially a desired pulse-to-pulse phase relationship for the received plurality of echo pulses of each look of each beam in a time-shared manner of signals associated with each look of the transmitted beams and to adaptively position an identified group of clutter signals about a prespecified dopper frequency in a derived doppler frequency spectrum for each look of each beam. The clutter positioning system may be disposed in either the transmission portion or the reception portion of the radar in which case it effects substantially the desired pulse-to-pulse phase relationship at each transmitted or received R.F. pulsed beam, respectively | Hopwood Francis W. (Severna Park, MD), Gipprich John W. (Catonsville, MD) | Westinghouse Electric Corp. (Pittsburgh, PA) | 24.01.1983 | 29.04.1986 | G01S13/00, G01S7/282, G01S7/28, G01S13/524, G01S013/52, G01S7/282, G01S13/5242 | 06/460688 |
| 140 | 4575723 | Foliage clutter rejector | Signals from a balanced processor are sampled at a constant rate, integra and then divided by the number of samples. Two averages are obtained:a positive half cycle average and a negative half cycle average. Over a long period, clutter contributions tend to cancel. Target dominance is thus enhanced by integrating over half cycles rather than full cycles. A single cycle bias finder adds half cycle averages to obtain a cycle bias. The single cycle bias is fed to the moving average integrator where it is integrated over an optimum number of cycles. Obtaining the moving average reduces the chance that a single cycle bias can cause the average to exceed the threshold while a radially moving target will be detected | Turner Donald G. (Ridgecrest, CA), Pogge R. David (Ridgecrest, CA) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 16.02.1982 | 11.03.1986 | G01S13/526, G01S13/00, G01S013/52, G01S13/526 | 06/349884 |
| 141 | 4559537 | Method of tracking target in presence of clutter | A method of operating a Doppler radar to track a target when main beam clutter is present is shown to comprise the steps of:(a) forming, from all signals exceeding a predetermined amplitude that are received by the pulse Doppler radar during a predetermined period, a range/Doppler matrix having NXM cells, where N is the number of range bins and M is the number of Doppler bins, with a digital one in any cell representative of a return signal with a given Doppler shift frequency from a reflector at a given range: (b) sequentially reading, in accordance with a predetermined program, the contents of the cells in the range/Doppler matrix to form digital numbers with digits indicative of the presence or absence of a reflector in adjacent cells: (c) comparing each digital number to a digital number representative of a target return signal: and (d) generating a frequency control signal when the comparison step indicates a target return signal to adjust a local oscillator in the pulse Doppler radar to effect tracking on the indicated target return signal | Pearson, Jr. Earl C. (Watertown, MA), Nelson William (Lexington, MA) | Raytheon Company (Lexington, MA) | 10.12.1982 | 17.12.1985 | G01S13/00, G01S13/524, G01S007/46, G01S013/04, G01S13/5242 | 06/448863 |
| 142 | 4463356 | Apparatus for control of clutter breakthrough in MTI radar | An apparatus for control of ground clutter breakthrough in MTI radar which remove hard limited clutter signals while allowing increased detection sensitivity to moving targets when such strong clutter returns are not present. Logic is provided to prevent the removal of strong moving target return even in the presence of hard limited clutter | Short, III Robert D. (Littleton, MA), Bennett, Jr. Clarence L. (Groton, MA), Barnes Richard M. (Acton, MA), Smith Robert S. (Acton, MA), Pyle Harold W. (Burnsville, MN) | Sperry Corporation (New York, NY) | 17.08.1981 | 31.07.1984 | G01S13/00, G01S13/526, G01S009/42, G01S13/526 | 06/293730 |
| 143 | 4459592 | Methods of and circuits for suppressing doppler radar clutter | Clutter suppressors and methods of clutter suppression for radars which employ the doppler effect for enhancing signals due to moving targets relative to signals due to clutter caused land, sea or rain. Specifically, the disclosure concerns suppressors and methods of clutter suppression for cw doppler, pulse doppler and MTI (moving target indication) radars. The suppressors reduce the occurrence of radar output due to clutter by permitting and prohibiting radar output on the basis of the relative strength of signals that contain doppler frequency components of the radar echo | Long Maurice W. (Atlanta, GA), Family ID | --- | 24.06.1981 | 10.07.1984 | G01S13/00, G01S13/524, G01S009/02, G01S13/524 | 06/278436 |
| 144 | 4430654 | Method and apparatus for suppressing clutter | A method and apparatus for automatic suppression of weather echoes or clutter which can disturbingly appear, apart from the flying target-Doppler signal as further Doppler signals in a pulse Doppler-tracking radar device containing quadrature channels, wherein there is regulated the frequency of the Doppler signals or the phase relationship between the Doppler signals and a reference signal derived from the transmitted signal | Kupfer Hanspeter (Uitikon, CH) | Siemens-Albis Aktiengesellschaft (Zurich, CH) | 28.06.1982 | 07.02.1984 | G01S13/00, G01S13/52, G01S013/00, G01S13/52 | 06/392624 |
| 145 | 4427982 | Radar clutter reduction by use of frequency-diverse, wideband pulse-compression waveforms | A method of and an apparatus for generating and transmitting wideband, exded radar pulses which spatially decorrelate clutter and are frequency-hopped from pulse to pulse by the proper frequency difference for clutter decorrelation by frequency-diversity are disclosed. The returned signals are compressed, delayed by one pulse interval and correlated, each with its succeeding echo pulse, to decorrelate the clutter returns but not the target echoes. The frequencies of the transmitted pulses are locked to the local oscillator frequency which is very stable. A double-sideband technique is used to generate the different pulse frequencies | Caprio Samuel J. (Severna Park, MD) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 28.04.1981 | 24.01.1984 | G01S13/00, G01S7/28, G01S7/282, G01S7/292, G01S13/24, G01S007/28, G01S7/282, G01S7/2923, G01S13/24 | 06/258346 |
| 146 | 4394658 | Adaptive MTI clutter tracker-canceller method and apparatus | An adaptive clutter canceller for adaptively cancelling clutter with non-zero mean Doppler frequencies. Received clutter signals averaged over a predetermined number of range cells and over an azimuth extent. The resulting averaged signal is used to shift the clutter spectrum to a zero mean Doppler and subsequently cancelled | Short, III Robert D. (Littleton, MA) | Sperry Corporation (New York, NY) | 27.03.1981 | 19.07.1983 | G01S13/00, G01S13/524, G01S013/52, G01S13/5244 | 06/248617 |
| 147 | 4381508 | Clutter compensated sidelobe cancelling communications system | A communications system including main and auxiliary antennas for reducing sidelobe interference with circuitry included in the feedback loop for estimating clutter by determining the difference between repetitious signals and subtracting a portion of the difference in the proper time sequence, relatively rapid changes between repetitous signals being composed generally of clutter | Durboraw, III Isaac N. (Scottsdale, AZ) | Motorola Inc. (Schaumburg, IL) | 12.03.1979 | 26.04.1983 | G01S7/28, H01Q3/26, G01S001/14, G01S7/2813, H01Q3/2629 | 06/019379 |
| 148 | 4371873 | Clutter free synthetic aperture radar correlator | A synthetic aperture radar correlation system including a moving diffuser located at the image plane of a radar processor. The output of the moving diffuser is supplied to a lens whose impulse response is at least as wide as that of the overall processing system. A significant reduction in clutter results | Frosch Robert A. Administrator of the National Aeronautics and Space (N/A), N/A (Pasadena, CA), Jain AtulFamily ID | --- | 08.12.1977 | 01.02.1983 | G01S13/90, G01S13/00, G01S013/89, G01S013/90, G01S13/9005 | 05/858767 |
| 149 | 4359738 | Clutter and multipath suppressing sidelobe canceller antenna system | An improved antenna and interference-cancelling system for improving signal ampling, particularly in side-lobe canceller system operating in a multiple-interference-source environment. An antenna is constructed as a circularly symmetric lens having loosely coupled feed elements disposed around the periphery of the lens. Each feed element acts as a high-azimuth-gain antenna which permits signal reception from all directions. The lens, when connected to couple the receiving feed elements to a side-lobe canceller, permits the canceller to discriminate against clutter and scattered signals and resolve interference sources in angle so that all canceller loops do not receive signals from all other interference sources, while still providing interference samples from all directions | Lewis Bernard L. (Oxon Hill, MD) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 09.08.1977 | 16.11.1982 | H01Q3/26, H01Q19/00, H01Q19/06, H01Q109/06, H01Q3/2617, H01Q19/06 | 05/824574 |
| 150 | 4318101 | MTI Radar comprising a processor selectively operable as a Weibull and a Rayleigh clutter suppressor | In an MTI radar receiver, a clutter suppressor (46, 47, 48) is switched (72), under the control of a discriminating device (71) responsive either to the shape parameter .eta. of the Weibull distribution or an average level of a clutter suppressed signal, to be selectively operable as a Weibull and a Rayleigh clutter suppressor for best possible LOG/CFAR processing with simple cell averaging circuitry. The suppressor may comprise a first processor (61) combined with an .eta. parameter calculator (48) for converting the Weibull clutter to the Rayleigh clutter, a second processor (89) for timing, and a simple suppressor (62) for the Rayleigh clutter. (FIG. 6) | Musha Toshimitsu (Tokyo, JP), Sekine Matsuo (Tokyo, JP), Kiuchi Eichi (Tokyo, JP), Irabu Takeru (Tokyo, JP) | Nippon Electric Co., Ltd. (Tokyo, JP) | 11.03.1980 | 02.03.1982 | G01S7/292, G01S013/52, G01S7/2927 | 06/129457 |
| 151 | 4318100 | Automatic ground clutter rejection in weather pulse radar system | In a weather radar system wherein echo signals are linear-detected from the waves received at the radar, each one of echo signals being compared with the later one to derive AC component, and the mean power of the weather echo estimated from the power of the AC component, the linear-detected echo signals are amplitude suppressed before compared. The amplitude suppression effectively removes the errors due to the fluctuation of ground clutter, and the variation of AC power of weather echo due to the existence of ground clutter. An amplitude suppressor is used which has an amplitude suppressing property expressed by Y=X.sup.k, where X is an amplitude of the input signal, Y is an amplitude of the output signal, and k is a constant (0<:k<:1). The value of k is advantageously 0.3-0.9, and, more advantageously 0.6-0.7. If the echo signals are obtained in a form of a logarithmic signal, an amplitude suppressor which has an input-output characteristic expressed by, for example, Y=10.sup.kZ/20 (Z:amplitude of input signal, Y:amplitude of output signal) can be used | Shimizu Toshio (Mitaka, JP), Wakabayashi Atsushi (Mitaka, JP), Goto Shuichi (Mitaka, JP) | Japan Radio Company, Limited (Tokyo, JP) | 19.02.1980 | 02.03.1982 | G01S13/95, G01S13/522, G01S13/00, G01S013/95, G01S13/522, G01S13/951 | 06/122498 |
| 152 | 4318099 | Clutter filter using a minimum number of radar pulses | A clutter filter which reduces by (N-1) the number of input pulses required or operation of an N-pulse MTI canceler when L>:N consecutive filtered outputs are desired. The clutter filter includes the two channels of an N-pulse MTI canceler which weight and sum the in-phase and quadrature-phase components of N radar returns, and a pair of delay circuits which introduce a delay of N interpulse time periods to the N and subsequent in-phase and quadrature-phase components of the radar returns. The stored outputs of the two channels of the canceler and the consecutive outputs of the delay circuits are combined in a complex multiplier to generate the consecutive in-phase and quadrature-phase outputs of the filter. The clutter filter has utility in a multiple-stage filter system employing a Doppler filter as the last stage | Hsiao James K. (Oxon Hill, MD) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 21.02.1980 | 02.03.1982 | G01S13/00, G01S13/526, G01S013/52, G01S13/526 | 06/123338 |
| 153 | 4296415 | Method and apparatus for reducing the effects of scintillation and rejection of clutter in monopulse radars | A method and apparatus for processing monopulse radar return signals to synthesize the imaginary component (.beta..sub.I) of the complex angle of arrival. Scintillation errors in the real component (.beta..sub.R) of the complex angle of arrival can then be reduced on a pulse-by-pulse basis by the criterion that .vertline..beta..sub.I .vertline. be small in magnitude and gating the .beta..sub.R signal when this criterion is not met | Pelton Frank M. (Clarence, NY), Miller Clyde A. (Falls Church, VA), Leney Thomas F. (Elma, NY) | Calspan Corporation (Buffalo, NY) | 06.02.1974 | 20.10.1981 | G01S13/00, G01S13/44, G01S013/44, G01S13/4427 | 05/441201 |
| 154 | 4290066 | High speed adaptive clutter filter | Method and apparatus for eliminating the effects of clutter in a coherent pulsed Doppler radar including determining the center frequency of the clutter and periodically moving the local oscillator frequency so that the clutter is shifted out of the Doppler filter passband, leaving only targets in the passband | Butler Walker (Scottsdale, AZ) | Motorola Inc. (Schaumburg, IL) | 12.10.1979 | 15.09.1981 | G01S7/285, G01S7/288, G01S007/28, G01S7/288 | 06/084265 |
| 155 | 4249179 | Circuit arrangement for displacing the clutter spectrum in a radar receiver | A circuit for a pulse Doppler radar receiver in which a measuring signal for determining the mean frequency of disturbing low frequency received clutter signals is obtained from which there is determined a control signal for operating a circuit that precedes the clutter filter and serves to displace the clutter spectrum into the blocking ranges of the fixed clutter filter particularly for radar devices having a non-constantly scanning antenna and wherein the circuit for determining the mean change in the clutter phase is in parallel with a delay device which has a delay that extends over a number of radar periods and wherein the circuit for determining the mean change in the clutter phase is preceded by an adjustable phase shift device which is followed by an accumulator for the addition of phase change and wherein continuous adjustment of an adjustable phase shift device is accomplished with a return loop and in which a switch is provided between the circuit for determining the mean change in the clutter phase and the accumulator which is closed at the end of each radar period for the transmission of measuring values | Kolacny Peter (Unterpfaffenhofen, DE) | Siemens Aktiengesellschaft (Berlin & Munich, DE) | 24.07.1978 | 03.02.1981 | G01S7/292, G01S007/28, G01S013/52, G01S7/2923 | 05/927283 |
| 156 | 4231037 | Radar clutter suppressor | This disclosure describes a radar clutter suppressor and target classifier that compares two or more video signals. Various signal conditioning and processing means are used for enhancing echo differences between targets and clutter caused by differences in polarization, carrier frequency, pulse length, antenna beamwidth, and antenna pointing direction. Signals are processed as if due to targets if the ratio of the video amplitudes are within a band of ratios and signals are suppressed as if due to clutter if the ratios are not within the band of ratios designated for targets. The invention includes methods for suppressing clutter caused by rain, land and sea | Long Maurice W. (Atlanta, GA), Family ID | --- | 23.02.1978 | 28.10.1980 | G01S13/00, G01S7/02, G01S13/87, G01S7/292, G01S013/00, G01S7/025, G01S7/292, G01S13/87 | 05/880624 |
| 157 | 4185285 | Radar for the detection of fixed targets in clutter | A high range resolution FM-CW radar system, having a range resolution cell of a target. Circuits are included for evaluating the difference between the echo intensity received from a resolution cell containing a highly reflective point of a target and that received from a resolution cell located at the same distance but containing only clutter | Bosc Henri J. (Paris, FR) | International Standard Electric Corporation (New York, NY) | 17.04.1978 | 22.01.1980 | G01S13/32, G01S13/00, G01S009/02, G01S13/32 | 05/897768 |
| 158 | 4170008 | Clutter discriminating fuze apparatus | A clutter discriminating fuze apparatus for preventing prefires and duds which may result through the use of electronic countermeasure techniques by the enemy | Goebel Robert H. (Bridgeton, MO), Fogle Dale A. (St. Louis Township, St. Louis County, MO) | The United States of America as represented by the Secretary of the Air (Washington, DC) | 28.02.1975 | 02.10.1979 | F42C11/00, G01S13/32, G01S7/36, G01S13/00, F42C013/04, G01S009/37, F42C11/00, G01S7/36, G01S13/32 | 05/553360 |
| 159 | 4151523 | Clutter mapper logic system | A receiving antenna connected to a surveillance sensor feeding a target detector. The target detector provides multiple inputs of target reports, azimuth, range and scan count data into a clutter mapper circuit which in turn feeds a track-while-scan circuit feeding a CRT display. The clutter mapper circuit provides improved clutter detection in the presence of scintillating clutter conditions | Platt Vernon H. (Fullerton, CA), Wilmot Richard D. (Buena Park, CA) | Hughes Aircraft Company (Culver City, CA) | 25.08.1976 | 24.04.1979 | G01S7/04, G01S7/06, G01S7/292, G01S007/44, G01S7/06, G01S7/2927 | 05/717711 |
| 160 | 4143371 | Arrangement for discriminating clutter signals from target signals in a radar system | An arrangement for protecting radars against unwanted echos such as "clutter" using an angular divergence measuring signal. This signal is compared with two predetermined thresholds + xo and - xo. When the probability of the two thresholds being exceeded by the divergence signal is greater than a predetermined value Po, the arrangement generates a logic signal which is used to prevent the tracking circuits of the radar from locking on to the received echo | Salvaudon Laurence (Paris, FR), Charlot Jean-Claude (Paris, FR) | Thomson-CSF (Paris, FR) | 11.10.1977 | 06.03.1979 | G01S7/285, G01S7/34, G01S13/00, G01S13/44, G01S7/292, G01S009/22, G01S7/2921, G01S7/34, G01S13/4418 | 05/840712 |
| 161 | 4139847 | Automatic ground-clutter rejection in weather pulse radar system | Ground clutter is automatically eliminated from echo signals in a weather pulse radar system to provide signals having an amplitude corresponding to the average intensity of the weather echo over a number of pulses. The reflected waves received in the receiver are linear-detected to provide echo signals. Each one of successive echo signals is compared with another later one which is apart from the each one echo signal by a predetermined time period during which fluctuation of weather target becomes independent, to derive an AC component signal corresponding to the fluctuation. The variance of the amplitude of the derived signal is proportional to the mean power of the weather echo. Thus, the ground clutter and the DC component of the weather echo are eliminated. The AC component signals are unipolarized and, thereafter, averaged. The averaged signals have an amplitude corresponding to the average intensity of the weather echo. These averaged signals may be logarithmic-converted to provide logarithmic signals similar as in weather radar system employing radar receivers having a logarithmic characteristic | Shimzu Toshio (Mitaka, JP), Goto Shuichi (Mitaka, JP) | Japan Radio Company, Limited (Tokyo, JP) | 15.06.1977 | 13.02.1979 | G01S13/95, G01S13/00, G01S009/60, G01S13/951 | 05/806679 |
| 162 | 4122450 | Infinite ratio clutter detecting system | An automatic clutter detecting and mapping system in which the area being mapped is broken up into clutter mapping quantum areas with corresponding storage cells including reject codes for automatically rejecting clutter returns which may occur in intermittent or fading clutter occurring a small percentage of the time for example. For each clutter mapping cell a clutter count and a reject code are stored in a main memory and in a first mode which is searching for clutter the clutter count is incremented by eight in response to an input targert but is not decremented in the absence of a received target from that clutter mapping area. In any clutter mapping cell when the clutter count reaches a threshold within a selected number of scan periods, the reject code is set to the amplitude corresponding to the maximum amplitude target report received in that cell and provided by a temporary memory. At this time, the clutter count is set to the midrange of its threshold value and the operation goes into a second mode which is searching for changes in the amplitude of the clutter. In the second mode of operation the counter bits for each mapping cell are incremented and decremented by selected values as a function of the target amplitude, with the reject code being set to a new target amplitude value of the report when a threshold is reached and the counter is again set to mid range. If the counter value reaches zero and the clutter has faded, the reject bits are set to zero and the operation is returned to the first mode | Kowalski Francis W. (Fullerton, CA), Wilmot Richard D. (Buena Park, CA) | Hughes Aircraft Company (Culver City, CA) | 16.06.1975 | 24.10.1978 | G01S7/292, G01S007/30, G01S7/2927 | 05/587176 |
| 163 | 4119966 | Clutter discriminating apparatus for use with pulsed doppler radar systems and the like | In apparatus for discriminating targets from clutter, a high threshold circuit for passing only signals with sufficient amplitude and a lower threshold circuit passing signals of a sufficient amplitude to range extent circuitry, which passes only signals within a predetermined duration and which do not have other range signals adjacent thereto, and to frequency extent circuitry, which passes only signals within a predetermined bandwidth and which do not have other frequency signals adjacent thereto. Signals which satisfy the amplitude, range and frequency requirements then provide an output indicative of a target: all other signals are rejected as clutter | Bouvier David William (Tempe, AZ), Brenner Charles H. (Scottsdale, AZ), Butler Walker (Scottsdale, AZ) | Motorola Inc. (Schaumburg, IL) | 14.07.1977 | 10.10.1978 | G01S7/292, G01S009/42, G01S7/2921 | 05/815760 |
| 164 | 4109247 | Clutter free communications radar | A clutter immune radar where the interrogating unit transmits a modulated interrogation signal to a remote unit, which radiates an unit to obtain remote unit information and range by the use of three bandpass filter channels where one bandpass filter bandwidth is equal to the sum of the other two bandwidths | Kaplan Gerald Stanley (Lawrenceville, NJ) | RCA Corporation (New York, NY) | 16.02.1977 | 22.08.1978 | G01S13/76, G01S13/00, G01S009/56, G01S009/58, G01S13/765 | 05/769337 |
| 165 | 4104631 | Method and system for clutter blanking in a radar target processor | In a radar system such as Doppler radar, clutter is eliminated without a requirement for somewhat sensitive frequency spectrum positioning. Processed returns are integrated over different halflook periods, where a look period is a period of constant pulse repetition frequency, and multiplexed into a postprocessor. The postprocessor measures the presence of clutter, and provides a blanking signal for clutter returns during portions of an operating cycle corresponding to clutter peaks | Weigle Wayne L. (Ellicott City, MD), Fogle Edgar L. (Severna Park, MD), Cromer Oscar M. (Baltimore, MD), Schafer Larry C. (Glen Burnie, MD) | Westinghouse Electric Corp. (Pittsburgh, PA) | 01.04.1976 | 01.08.1978 | G01S13/00, G01S13/524, G01S13/526, G01S007/44, G01S13/5242, G01S13/5246, G01S13/5265 | 05/672823 |
| 166 | 4093949 | Clutter tracker using a smoothed doppler frequency measurement | A clutter tracker in which received clutter velocity signal is shifted to cancellaton can be achieved is disclosed. A frequency controllable voltage controlled crystal oscillator (VCXO) is used as the coherent oscillator (COHO) source. The subject digital system changes the VCXO output bus only once per dwell, thus allowing adequate filtering to achieve desired performance without adversely affecting tracking performance | Evans Norol T. (San Pedro, CA) | Hughes Aircraft Company (Culver City, CA) | 26.05.1976 | 06.06.1978 | G01S13/524, G01S13/00, G01S009/02, G01S009/42, G01S13/5244 | 05/690330 |
| 167 | 4075571 | Externally biased video detector circuit for limiting clutter and noise in a detected radar signal | A video detector circuit for a radar system, including a detector diode having one of its electrodes connected to an input terminal for detecting an applied signal containing target information, rms noise voltage and components that are representative of clutter, and its other electrode connected to a load terminal for providing a detected signal: and a load resistance connected between the load terminal and a bias terminal: wherein a dc potential is provided at the bias terminal to forward bias the detector diode to have a quiescent operating point below the midpoint of the knee portion of its characteristic curve, thereby limiting diode rms noise current and components in the detected signal that are representative of clutter. As a result both the signal-to-noise ratio and the target-to-clutter ratio of the video detector circuit are enhanced. A filter network is connected between the load terminal and an output terminal for providing an output signal at the output terminal in which low frequency components representative of clutter in the detected signal are suppressed | Hulderman Garry N. (Riverside, CA), Winderman Jay B. (Claremont, CA) | General Dynamics Corporation (Pomona, CA) | 08.06.1977 | 21.02.1978 | G01S7/28, H03D1/00, H03D1/10, H03D1/06, H03K009/00, H03K019/12, G01S7/28, H03D1/06, H03D1/10 | 05/804671 |
| 168 | 4074264 | Adaptive threshold clutter processor | A time sampling adaptive clutter processor that samples on a scan to scan basis rather than on an area basis and in response to signals received from the object being interrogated develops a mean level value and a standard deviation value. The mean value and the standard deviation value may be provided by recursive type filters operating with scan to scan memories. The mean level value is then combined with the standard deviation value to provide a threshold that provides improved clutter detection especially with a condition in which a clutter variation from scan to scan is less than the clutter variation between areas in any one scan. The system may also include a valid target control to eliminate the detrimental effects on the threshold that may be caused by targets being tracked | Wilmot Richard D. (Buena Park, CA) | Hughes Aircraft Company (Culver City, CA) | 07.01.1976 | 14.02.1978 | G01S7/28, G01S7/292, G01S007/30, G01S009/02, G01S7/2806, G01S7/2923 | 05/647226 |
| 169 | 4068231 | Automatic clutter-mapper | A system for detecting the presence of clutter utilizing an area overlap technique that effectively rejects scintillating position clutter near the boundaries of the area clutter map ACM cells. A first area clutter-mapper system is provided with its area ACM cells at a first position and a second clutter-mapper system is provided with its ACM cells in a second position with each cell displaced by about one-half ACM cell dimension in range and azimuth to overlap the original ACM cell boundaries. All of the clutter returns which were divided among the original set of ACM cells occur in one of the area overlap ACM cells so that when the clutter scintillates between ACM cells for any selected detection criterion, it is identified as clutter rather than a moving target. Separate detection history counts for clutter-identification and inhibit code for clutter rejection are provided in both the first and second clutter overlap map units. A clutter rejection code or condition in either area map unit will determine that clutter is present and the control gate samples either the clutter amplitude or a cluster code in both the first and second ACM cell units and rejects target signals if clutter has been determined in either of the units. In one modeling of the concept of invention, it was found that the area overlap method increased the amount of clutter rejected by 55% over a conventional single ACM mapping system unit | Wilmot Richard D. (Buena Park, CA) | Hughes Aircraft Company (Culver City, CA) | 02.09.1976 | 10.01.1978 | G01S7/292, G01S009/02, G01S7/2923 | 05/721628 |
| 170 | 4067012 | Tracking feedback clutter mapper control device | An antenna is connected to a surveillance sensor feeding a target detector. The target detector provides multiple inputs of target reports, azimuth, range and scan count data to a clutter mapper circuit which in turn feeds a track-while-scan circuit one output of which is fed back to a data input buffer also feeding the clutter mapper circuit. Another output of the track-while-scan circuit provides input to a CRT display | Platt Vernon H. (Fullerton, CA), Wilmot Richard D. (Buena Park, CA) | Hughes Aircraft Company (Culver City, CA) | 25.08.1976 | 03.01.1978 | G01S13/72, G01S13/00, G01S007/46, G01S13/72 | 05/717712 |
| 171 | 4064511 | Clutter subtraction system | A radar system having transmitted and received signals, the system including a feedback loop for modulating a sample of the transmitted signal to duplicate the phase and amplitude of the clutter echoes from nearby points of reflection. The modulated transmitted sample is subtracted from the received signal to remove the clutter. The feedback loop detects differences between the clutter-free signal and the transmitted sample to produce an error signal, the error signal being filtered and applied to the modulator for modulating the phase and amplitude of the transmitted sample. BACKGROUND OF THE INVENTION This invention relates to echo ranging systems such as radar and sonar systems and, more particularly, to an echo ranging system in which clutter returns from nearby objects are removed from echoes from distant objects. Echo ranging systems frequently utilize transmitted pulses of radiant energy in which the duration of the pulse is equal to a substantial portion of the overall round trip time of propagation of radiant energy signals from the echo ranging system to a distant object and back to the echo ranging system. The use of a long duration pulse of radio frequency energy permits the transmission of a large amount of radiant energy as compared to that which can be transmitted in a relatively short pulse from transmitting equipment which is limited in its maximum peak power capability. To produce enhanced discrimination in range between closely spaced reflecting objects, the spectrum of the transmitted pulse of radiant energy is broadened by a modulation of the carrier, such modulation being typically a phase modulation of the carrier, one such form of phase modulation employing a quadratic phase shift pattern which results in a frequency modulation pattern in the form of a linear sweep. Such a modulation pattern is conveniently employed with pulse compression filters in radar and sonar receiving equipment for the discernment of closely spaced points of reflection. A problem arises in that echo ranging systems are frequently employed in situations wherein nearby objects of reflection and distant objects of reflection, often referred to as targets, are simultaneously present. While the leading edges of echoes from nearby targets arrive at the radar or sonar system prior to the leading edges of echoes from distant targets, the relatively long duration of the transmitted pulses may result in extensive overlap of the major portion of the echoes of nearby targets with the echoes from distant targets. When the aforementioned linear sweep frequency modulation is employed, the instantaneous frequency of a portion of an echo from a nearby target differs from the instantaneous frequency of an overlaping portion of an echo from a distant target. Furthermore, the amplitude of an echo from a nearby target, such as the echo from a wave in a sea clutter situation, is much larger than the amplitude of the echo received from a distant target. In view of these differences in frequency, or phase, and amplitude of the echoes, the clutter of echoes from the nearby targets masks the echoes from the distant targets. Difficulties are encountered in echo receiving equipment in that automatic gain control used therein must have a large dynamic range to accommodate the large and the small amplitude echo signals. Such automatic gain control equipment, when tracking the large amplitudes of the clutter, tends to distort the waveforms of the echoes received from the distant targets with a resulting loss in data obtainable from such distant targets. The foregoing situation relates to both electromagnetic and sonic echo ranging systems and, since the invention to be described hereinafter applies to both electromagnetic and sonic echo ranging systems, the ensuing description will be given in terms of a radar system, it being understood that the description relates equally well to a sonar system. SUMMARY OF THE INVENTION The aforementioned problems of the prior art are overcome and other advantages are provided by a radar system having transmitted and received signals, and which, in accordance with the invention, modulates a sample of the transmitted signal to substantially duplicate received clutter signals, the modulated sample being subtracted from the received signal to provide a received signal free of clutter. In a preferred embodiment of the invention, the transmitted signal is phase modulated quadratically with time, this being a linear frequency sweep over the duration of the transmitted signal pulse. Such modulation provides a transmitted signal having an increased bandwidth suitable for the pulse compression of received signal echoes. In accordance with the invention, the aforementioned subtraction of the transmitted signal sample is accomplished by a feedback loop in which the clutter-free signal is compared to the transmitted sample by a detection of inphase and quadrature components of the clutter-free signal to develop an error signal of the feedback loop. The error signal is then filtered and applied to a modulator which modulates the phase and amplitude of the transmitted sample to match the phase and amplitude of the clutter. Thereby, the clutter component of the received signal may be subtracted from the received signal. The bandwidth of the feedback loop provides a sufficient speed of response for tracking clutter of nearby reflecting objects for which the frequency and phase of the echo approximates that of the transmitted signal phase. The loop bandwidth is sufficiently narrow to preclude the tracking of echoes from distant reflecting objects for which the frequency of the echoes differs substantially from that of the transmitted signal pulse. Thereby, distant objects, or targets can be observed since the echoes therefrom are essentially unaffected by the feedback loop | Manfanovsky Serge (Wayland, MA) | Raytheon Company (Lexington, MA) | 24.09.1976 | 20.12.1977 | G01S13/26, G01S13/00, G01S7/292, G01S007/02, G01S7/2921, G01S13/26 | 05/726345 |
| 172 | 4042924 | MTI clutter tracking and cancelling system | A clutter tracking and cancelling system, for use in a MTI radar system, comprising an auxiliary channel consisting primarily of a phase detector and a canceller. The phase detector provides an output which represents the phase difference between the IF and the coho output, while the output of the canceller, which responds to the phase detector output, represents clutter MTI residue from one transmission to the next. Clutter MTI residue from several successive range bins is smoothed and integrated to provide a control output which is used to shift the phase of the coho frequency, which is supplied to the phase detector in the conventional main MTI produce optimum clutter cancellation in the main MTI channel | Evans Norol T. (San Pedro, CA), Wunderlich Francis J. (Placentia, CA) | Hughes Aircraft Company (Culver City, CA) | 25.02.1970 | 16.08.1977 | G01S13/526, G01S13/00, G01S009/42, G01S13/5265 | 05/017992 |
| 173 | 4041489 | Sea clutter reduction technique | A multi carrier-frequency pulsed radar system in which each carrier-frequy reflected radar signal is separately processed by parallel receiver branches. The output of each receiver branch is multiplied together to form the product of the separate receiver outputs, which product is then displayed on a plan-position-indicator (P.P.I.) display | Lewis Bernard L. (Oxon Hill, MD) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 25.06.1974 | 09.08.1977 | G01S13/00, G01S13/10, G01S7/292, G01S007/28, G01S7/292, G01S13/106 | 05/482970 |
| 174 | 4040057 | Clutter filter for Pulse Doppler Radar | The invention provides an improved clutter filter for a Pulse Doppler Radar utilizing rapidly changing p.r.f.'s. The filter is designed to reduce the effect of spectrum spreading which has previously caused difficulties | Cross Malcolm Geoffrey (Colchester, EN), Dawson John Howard (Chelmsford, EN) | The Marconi Company Limited (EN) | 03.11.1975 | 02.08.1977 | G01S13/00, G01S13/22, G01S13/53, G01S007/28, G01S13/22, G01S13/53 | 05/628544 |
| 175 | 4035799 | Digital mean clutter doppler compensation system | A digital technique is disclosed for filtering clutter in a pulse doppler I radar which allows a filter notch to be set for different doppler frequencies. In particular, the system includes two or more MTI filters cascaded to cancel different kinds of clutter signals that interfere with target signal reception. In each filter a digital detection circuit senses the mean-clutter-doppler frequency for a particular clutter type and automatically places a notch at that frequency. Each notch is fixed by treating the radar samples as complex numbers and replacing the conventional filter coefficients with complex coefficients indicating amplitude and phase as derived from the radar returns | Hsiao James K. (Oxon Hill, MD) | The United States of America as represented by the Secretary of the Navy (Washington, DC) | 04.11.1975 | 12.07.1977 | G01S13/526, G01S13/00, G01S13/64, G01S009/42, G01S13/5265, G01S13/64 | 05/628631 |
| 176 | 4028697 | Adaptive signal processor for clutter elimination | An adaptive signal processing system for enhancing the signal-to-interference characteristics of a pulse radar system exposed to clutter signals as well as to desired target signals is disclosed. The time-extended clutter signals, along with specially generated phase reference signals are employed in a multi-element adaptive filter-correlator system to reduce the clutter presence in the radar receiver output to a minimum value for all target ranges and for both volume and surface clutter | Albanese Angelo P. (Brooklyn, NY), Rattiner David H. (Great Neck, NY) | Sperry Rand Corporation (New York, NY) | 08.09.1970 | 07.06.1977 | G01S7/292, G01S009/42, G01S7/2923 | 05/070194 |
| 177 | 4006351 | Recursive filter implemented as a matched clutter filter | In a recursive (zeros and poles) filter having input and output signals y and y.sub.o and having impulse response h.sub.r apparatus and method for obtaining the convolution y.sub.o = y * h.sub.r using either the convolution integral or using the discrete Fourier transform (DFT). When using the convolution integral the apparatus first computes the impulse response h.sub.r then obtains the response y.sub.o in a convolver while when using the DFT the apparatus first computes the transfer function H.sub.r then obtains the frequency spectrum Sy.sub.o of response y.sub.o. By implementing the recursive filter as a matched clutter filter, the error normally associated with this type filter is minimized | Constant James Nickolas (Claremont, CA), Family ID | --- | 11.11.1974 | 01.02.1977 | G01S7/292, H03H17/02, H03H17/04, G06F015/34, G01S7/292, H03H17/0254, H03H17/04 | 05/522718 |
| 178 | 4003052 | Digital prefilter for clutter attenuation in MTI radars | In a digital moving target indicator (MTI) employing digital filters for rejecting low frequency clutter signals having magnitudes which are 20 to 60 db greater than the moving target return signal, the dynamic range and resolution accuracy requirement of an analog-to-digital (A/D) converter, used to convert the return radar analog video signal to a plurality of digital signal equivalents for presentation to the digital filters, is reduced from that normally required by prefiltering the return video signal through a prefilter network. The digital prefilter utilizes:a low converter to convert the return analog video signal (comprising both low frequency clutter and high frequency moving target component signals) to a digital signal, a low-pass digital filter to pass only the low frequency clutter signal, a digital-to-analog converter to reconvert the digital clutter signal to an analog clutter signal which is substantially equivalent to the clutter component signal value of the analog video signal, and a summing circuit which provides an analog sum signal representative of the amplitude difference between the analog clutter signal and the return analog video signal, to provide a video signal with a greatly enhanced moving target to clutter signal ratio. The sum signal is presented to the system A/D converter, permitting the use of a low resolution system A/D converter having a substantially reduced dynamic range and lower cost, the system A/D converter providing the digital equivalent signal of the enhanced return video for further processing in the digital MTI filters | Adelman Stephen (Wilton, CT), Greenspan Marshall (Fairfield, CT) | United Technologies Corporation (Hartford, CT) | 15.12.1975 | 11.01.1977 | G01S13/00, G01S13/52, G01S009/42, G01S13/52 | 05/641127 |
| 179 | 3995271 | Adaptive clutter cancellation and interference rejection system for AMTI radar | In an AMTI radar having digital doppler processing, adaptive clutter and interference rejection is achieved by automatically adjusting antenna phase and amplitude weights to trim for uncalibrated errors and to put nulls in the antenna receive patterns in the direction of the source of interference or jamming signals. Antenna weights are initially chosen to achieve an optimum signal to clutter ratio. The radar receive signals are averaged over many range cells, filtered and summed by adaptive processor circuits. Feedback loops adjust the antenna weights to minimize the summed output. The circuits effect this by mechanizing the steepest descent algorithm | Goggins, Jr. William B. (Locke Mills, UT) | The United States of America as represented by the Secretary of the Air (Washington, DC) | 20.08.1975 | 30.11.1976 | G01S13/00, G01S7/28, G01S13/524, G01S13/526, H01Q3/26, G01S009/42, G01S7/2813, G01S13/5244, G01S13/5265, H01Q3/2617 | 05/606624 |
| 180 | 3993994 | Adaptive clutter cancellation for synthetic aperture AMTI radar | Clutter cancellation between adjacent channels of a multichannel synthetic aperture AMTI radar is accomplished by delaying signals from the forward channel to coincide with signals from the aft channel and subtracting the outputs. Adverse effects from unknown, uncalibrated and time varying parameters are compensated for by adjusting the phase and amplitude of the aft channel coherent receiver output in response to the complex multiplier signal .omega.. The synthetic aperture processing circuit outputs of each channel are averaged over many range cells and summed to determine clutter magnitude. The complex multiplier signal .omega. is made to minimize the clutter magnitude by means of a steepest descent algorithm. A mathematical expression relating the complex multiplier signal .omega. to clutter magnitude for optimum clutter cancellation is developed and a circuit is provided for mechanizing the process | Goggins William B. (Locke Mills, ME) | The United States of America as represented by the Secretary of the Air (Washington, DC) | 27.06.1975 | 23.11.1976 | G01S13/90, G01S13/00, G01S7/292, G01S13/526, G01S009/42, G01S7/2921, G01S13/5265, G01S13/9023, G01S13/9029 | 05/590973 |
| 181 | 3972041 | Adaptive clutter velocity cancellation system for pulsed digital MTI system | A digital MTI radar system for improved handling of "moving clutter" which employs a double phase detector scheme to provide both Doppler sine and Doppler cosine terms which are separately digitally encoded in a series of range increments throughout each pulse repetition interval. The discrete digitally encoded values thus represent instantaneous echo signal phase angle in each corresponding range increment. This angle data is compared by range increments with that of the last previous pulse repetition period, to provide net signal phase angle change in digital form (a velocity related term) by range increments successively. The remaining circuitry comprises a device for sampling this net phase angle change over a predetermined number of range increments to compute average clutter velocity with respect to the radar system location. A bona fide signal in the moving clutter may then be recognized on the basis of its exceeding the average clutter velocity. A quantized output is effected by means of a logic arrangement which detects the condition of signal presence in one or two adjacent ones of the range increments provided these increments are preceded and followed by a predetermined relatively small number of range increments exhibiting no signal above the said average clutter velocity | Howard Shirly L. (Canoga Park, CA) | International Telephone and Telegraph Corporation (New York, NY) | 25.02.1975 | 27.07.1976 | G01S13/00, G01S13/524, G01S13/526, G01S009/42, G01S13/5242, G01S13/5244, G01S13/526 | 05/552926 |
| 182 | 3962704 | Moving target indicator clutter tracker | An improved MTI (Moving Target Indicator) cancelling system that provides cancellation in the first canceller stage of clutter at a first frequency and cancellation in a second or subsequent canceller stage of clutter such as weather or chaff with a substantial doppler frequency offset from that cancelled in the first MTI canceller. The first canceller stage may be a conventional in-phase (I) and in-quadrature (Q) digital MTI unit to develop the I and Q first differences followed by a conversion of these differences into a combined first difference designated as a quantity M and representing an angle times an amplitude multiplier. This M signal is then applied to a second canceller to develop a second difference signal which is then normalized to represent a pure angle term. A computer then determines the average angular error percentage over a selected number of adjacent range bins at each range bin interval and this percent error is then multiplied by the time aligned value of M to provide an actual error and a modified value of M is developed by subtracting the actual error from the value of M. The modified first difference signal is then subtracted from the delayed first difference signal to generate a second difference output signal with the undesired clutter at different doppler frequencies being cancelled | Evans Norol T. (San Pedro, CA) | Hughes Aircraft Company (Culver City, CA) | 31.05.1974 | 08.06.1976 | G01S13/00, G01S13/526, G01S009/42, G01S13/526 | 05/475217 |
| 183 | 3952280 | Radiation monitoring of an object space with a clutter suppression technique | A technique for monitoring an object space having known cluttering objects for determining when an object of interest enters the object space. An application of the technique is in sonar supervision of a river or other body of water wherein the entrance into the monitored space by the object of interest, such as a shark or swimmer, is readily detected. Such detection is accomplished by illuminating a monitored object space with broad band radiation. Radiation either reflected from or transmitted through the object is then converted to an electrical signal that is passed through a bank of bandpass filters. The filter outputs are weighted to maximize the receiver's response to the object of interest while minimizing the response to clutter and noise. The technique is based upon the observation that different reflectors give rise to different echo spectra when the reflectors are illuminated with a broad band signal | Altes Richard A. (Palo Alto, CA) | ESL Incorporated (Sunnyvale, CA) | 10.01.1974 | 20.04.1976 | G01S7/523, G01S7/527, G01S009/66, G01S007/66, G01S7/527 | 05/432169 |