Monopulse Patents (Class 342/149)
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Patent number: 7492306Abstract: An boundary monitoring apparatus comprising an object detection device arranged to transmit a signal into a detection region and to detect an object in said detection region upon receipt of a reflected signal from said object; means for defining a boundary in said detection region; means for determining a path of said object in the detection region; means for performing an evaluation of the determined path of the object with respect to the boundary; and means for causing an alarm event depending on the evaluation.Type: GrantFiled: March 24, 2006Date of Patent: February 17, 2009Assignee: TDK CorporationInventors: Denver Humphrey, Bryan Clarke
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Patent number: 7417584Abstract: A monopulse radar operating at low angles of elevation (LOE) receives returns from a target by a direct path and by a path including a reflection from that portion of the Earth's surface lying between the radar and the target. The surface-reflected signal tends to cause errors in the estimate of the elevation of the target. A radar system directs at least upper and lower overlapping beams at LOE toward the target for receiving returns. The upper and lower beams may be sequential or simultaneous. Real and imaginary portions of the sum (?) and difference (?) signals are generated for each beam. The monopulse estimates of elevation ê derived from the real portion of the ? and ? signals are processed to produce correction signals for upper and lower beams. Each correction signal is weighted and summed to correct the estimate of elevation.Type: GrantFiled: November 8, 1989Date of Patent: August 26, 2008Assignee: Lockheed Martin CorporationInventors: Frank Joshua Raphael Reifler, Randall Deen Morris
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Publication number: 20080122683Abstract: System and method for finding a direction of two or more secondary RF sources arrayed about a position of a primary RF source (X1). The system includes an antenna system (500) coupled to a monopulse tracking system (100) for determining a position of a primary RF source relative to a boresight axis (502) of the antenna system. The system includes a monopulse direction finding system (600) coupled to the antenna system responsive to RF signals from two or more secondary RF sources (Y1, Y2) having at least one of a different frequency and a different polarization as compared to the primary RF source.Type: ApplicationFiled: June 30, 2006Publication date: May 29, 2008Applicant: HARRIS CORPORATIONInventors: Robert J. Howley, William C. Daffron, Scott J. Hemlinger, Anthony J. Gianatasio
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Patent number: 7330149Abstract: A monopulse radar tracking method which analyzes boresight error information provided a monopulse radar to determine a location for two targets. The monopulse radar tracking method analyzes the boresight error information to determine an angle of arrival for a dominant target and a secondary target.Type: GrantFiled: February 9, 2006Date of Patent: February 12, 2008Assignee: The United States of America as represented by the Secretary of the NavyInventor: Shaun David Weatherford
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Publication number: 20080030395Abstract: A system for generating a pseudomonopulse tracking error includes an antenna system (401) that generates a sum antenna beam and a difference antenna beam. The sum antenna beam has a pattern with a peak gain on the boresight axis, and the difference antenna beam has a pattern that is circularly symmetric and forms a null about the boresight axis. The difference antenna beam has a relative phase that varies 360 degrees around the boresight axis. A differential phase dispersion is provided as between the sum and difference RF channels (405, 407) to providing a rotating scanning plane (702).Type: ApplicationFiled: August 7, 2006Publication date: February 7, 2008Applicant: HARRIS CORPORATIONInventors: Earl Knick, James K. Conn, Larry P. Serulneck
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Publication number: 20070279276Abstract: System for dynamically tracking a position of a target with an antenna in a communication system. The system includes an antenna system (410) configured for generating a sum and difference antenna pattern (201-1, 201-2). A sum RF channel (401) is coupled to a sum channel output of the antenna system. A difference RF channel (402) is coupled to a difference channel output of the antenna system. An RF coupler (422-1) is provided that has a first input coupled to the sum RF channel and a second input coupled to the RF difference channel. One or more coupling control devices (418-1, 418-2) selectively vary an effective coupling value as between the difference channel and the sum channel. An antenna tracking error signal is generated at an output of the coupler.Type: ApplicationFiled: May 31, 2006Publication date: December 6, 2007Applicant: HARRIS CORPORATIONInventors: James K. Conn, James B. Offner, Larry P. Serulneck, Earl B. Knick, Ron Hash, Ying-Ming Lee, Pete Denney, Joseph A. Elam, Brian A. Smith
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Patent number: 7292179Abstract: A method and apparatus for use in determining the range in a single time sample from a platform to a target are disclosed. The method includes receiving radiation emanating from the target at two points on the platform in a common time sample; detecting the received radiation and generating a signal representative thereof; and processing the signal. The signal is processed to determine a respective angle to target from two points on the platform by using a correlation between received signal amplitude and respective angle; and determine the range from the platform to the target from the respective angles and the separation distance between said two points in a single signal-to-noise sufficient sample. The apparatus includes a plurality of optical channels through which the apparatus can receive radiation emanating from the target, the optical channels and a plurality of electronics.Type: GrantFiled: April 11, 2005Date of Patent: November 6, 2007Assignee: Lockheed Martin CorporationInventors: Wayne K. Schroeder, Brett A. Williams
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Patent number: 7268724Abstract: This monopulse processor provides target position information having an RMS error which is less than that of a conventional monopulse processor. A ?±j? vs. ? processor is modified to provide a position output signal equal to the smaller in absolute magnitude of the results obtained from the ?+j? vs. ? and the ??j? vs. ? processing. A conventional monopulse processor is modified to provide an output signal having a value equal to Re(?/?)/[1+|Im(?/?)|].Type: GrantFiled: December 23, 1981Date of Patent: September 11, 2007Assignee: Lockheed Martin CorporationInventor: Samuel Mark Sherman
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Patent number: 7262729Abstract: A radar system having a processor, a waveform generator, a plurality of antenna interfaces, a set of first antennas configured to transmit a waveform, and a set of second antennas configured to receive a reflected waveform is disclosed. The waveform generator and antenna interfaces are in control and signal communication with the processor, each of the first antennas are in signal communication with one of each antenna interface, and each of the second antennas are in signal communication with one of each antenna interface. The waveform generator is in control and signal communication with each antenna interface, and is configurable to generate a waveform conforming to at least two ISM bands. Each first antenna is configured to transmit a circularly polarized electromagnetic waveform, and each second antenna is configured to receive a reflected circularly polarized electromagnetic waveform complementary to the first antennas.Type: GrantFiled: June 19, 2006Date of Patent: August 28, 2007Assignee: General Electric CompanyInventors: John Erik Hershey, Ralph Thomas Hoctor, David Michael Davenport, Jeffrey Michael Ashe, Richard Louis Frey, Kenneth Brakeley Welles, V. Paul Staudinger, Harold W. Tomlinson, Jr.
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Patent number: 7250902Abstract: A method and apparatus for generating accurate estimates of a radar target's azimuth and elevation angles for a phased-phased array rotating radar. Scan modulated coherently integrated (SMCI) monopulse curves are generated from a measured one-way transmit antenna pattern and three receive antenna patterns. The SMCI monopulse curves are calculated in advance for the expected beam steers. To utilize the SMCI monopulse curves, two-way Sum, Delta-Azimuth and Delta-Elevation target returns are coherently integrated, the target's monopulse ratios calculated, and the SMCI monopulse curves or polynomials used to calculate the target's U-offset and V-offset sine-space angles, which are added to the radar's beam steer to get an improved estimate of the target's sine-space angular position denoted as Utgt and Vtgt. A coordinate system transformation transforms Utgt and Vtgt to azimuth and elevation angles in a non-rotating coordinate system.Type: GrantFiled: July 19, 2005Date of Patent: July 31, 2007Assignee: Raytheon CompanyInventors: David V. Manoogian, Gerald M. Pitstick, John Cangeme
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Patent number: 7236125Abstract: A method for reducing angular blur in radar pictures achieved in range bin based detection systems includes measuring a variable S(x, y) such as amplitude or power as a function of an angle x and a distance y. An expression: corrected angular position=angular position+angle correction is determined in each range bin for a plurality of angular values x. The term “angle correction” includes derivative(s) of first or higher order of the variable S(x). The variable measured at the angular position “angular position” is moved to the variable in the angular position “corrected angular position”, and the moved variable and the variable in “corrected angular position” are processed by adding or maximizing the values.Type: GrantFiled: January 25, 2005Date of Patent: June 26, 2007Assignee: SAAB ABInventor: Bert-Eric Tullsson
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Patent number: 7218273Abstract: A technique for boresighting an antenna mounted on a moving platform is described. The technique uses a concurrently moving calibration target. Target navigation data and platform navigation data are used to compensate for movement of the target and the platform. The antenna pointing direction is biased in a direction which provides a best signal quality, and the bias used to determine antenna boresight calibration factors. The boresight correction factors can be used for open loop pointing.Type: GrantFiled: May 24, 2006Date of Patent: May 15, 2007Assignee: L3 Communications Corp.Inventors: James B. Webster, Jr., LaMar K Timothy, Fred M. Strohacker
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Patent number: 7218272Abstract: Reducing antenna boresight error includes receiving radar pulses reflected from the ground, where pulses are emitted from the antenna of a radar system, reflected by the ground, and received by the antenna. The return pulses carry information about the ground. Measurement indices are established from radar and platform parameters, and a clutter spectrum is generated from the return pulse information. The amplitude of the clutter spectrum is measured at each of the measurement indices. Whether there is an amplitude imbalance is established in accordance with the measured amplitudes. An error estimate describing an antenna boresight error is determined if there is an amplitude imbalance.Type: GrantFiled: June 27, 2006Date of Patent: May 15, 2007Assignee: Raytheon CompanyInventor: David L. Steinbauer
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Patent number: 7212152Abstract: The present invention provides that a monopulse radar system to correct an amplitude error and a phase error developed between receiving channels and improve the accuracy of a detected angle. A part of a transmit signal is supplied to respective channels on the receiving side through a signal transmission line for calibration. At this time, the gains of a variable phase shifter and a variable gain amplifier are adjusted so that an azimuth angle of a pseudo target, based on a signal for calibration, which is calculated by signal processing means, reaches a predetermined angle. In the monopulse radar system of the present invention, calibration work is simplified and an angular correction can be automated. The present monopulse radar system of the present invention is capable of coping even with variations in characteristic after product shipment due to environmental variations and time variations in parts characteristic.Type: GrantFiled: April 6, 2004Date of Patent: May 1, 2007Assignee: Hitachi, Ltd.Inventor: Toshiyuki Nagasaku
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Patent number: 7205932Abstract: An improved system is provided for aiming a shotgun-based or other countermeasure system so as to be able to countermeasure incoming rockets or projectiles. In one embodiment a shotgun aimed and controlled by the subject system projects a pattern of pellets to intercept a rocket-propelled grenade or incoming projectile. The fire control system uses a CW two-tone monopulse radar to derive range and angle of arrival within 150 milliseconds, with range and angle of arrival measurements having approximately twice the accuracy of prior CW two-tone monopulse radars. The improvement derives from using all of the information in the returned radar beams and is the result of the recognition that one can use the Sum and Difference signals to assemble a two-by-two Rank One matrix that permits using singular value decomposition techniques to generate range and angle of arrival matrices in which all available information is used and in which noise is eliminated.Type: GrantFiled: October 1, 2004Date of Patent: April 17, 2007Assignee: BAE Systems Information and Electronic Systems Integration Inc.Inventor: Paul D. Fiore
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Patent number: 7190305Abstract: In a radar apparatus, a receiving antenna includes a plurality of antenna elements, each receiving, as a reception signal, radio waves emitted into space and reflected off a target object. An analog signal is obtained by downconverting and putting a bandwidth constraint on the reception signal, and is then converted to a digital signal. Based on the digital signal, a signal processing unit detects the bearing of the target object. The signal processing unit performs processing based on outputs of two sets of the antenna elements.Type: GrantFiled: March 3, 2005Date of Patent: March 13, 2007Assignee: Fujitsu Ten LimitedInventor: Osamu Isaji
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Patent number: 7162200Abstract: An antenna calibration system consists mainly of a signal source, an antenna, a first radio frequency mixer, a first local oscillator, an power detecting device, a personal computer, and a servo amplifier. The signal source emits a signal, and the antenna receives the signal. The signal and the first local oscillator, which emits a signal, are emitted into the first radio frequency mixer. Then the first radio frequency mixer emits a signal into the energy detecting device which calculates the signal power, and transmits the power into the personal computer. The personal computer calculates the powers, and then transmits an angle control signal into the servo amplifier. The servo amplifier amplifies the signal, and then drives the antenna pedestal to turn until the antenna is aimed at the signal source. This can calibrate exactly the antenna's azimuth and elevation offset angle.Type: GrantFiled: April 15, 2003Date of Patent: January 9, 2007Assignee: Chung Shan Institute of Science and TechnologyInventors: Jinn-Jy Tsay, I-Chung Sung
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Patent number: 7136014Abstract: An invention is provided for determining the azimuth pointing angle of a moving monopulse antenna. Pulses of energy are broadcast at the surface of a planetary body. Reflected signals are received from the surface of the planetary body using a plurality of feeds. A monopulse ratio is then calculated based on a sum pattern and a difference pattern. The sum pattern is based on the sum of the reflected signals received using the feeds, and the difference pattern is based on a difference of the reflected signals received using the feeds. An azimuth pointing angle of a monopulse antenna is then calculated using the monopulse ratio.Type: GrantFiled: November 23, 2004Date of Patent: November 14, 2006Assignee: The Boeing CompanyInventors: Henry McCord, Bernard Schweitzer, Eric B. Jensen, Steve A. Hallman
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Patent number: 7068215Abstract: Reducing antenna boresight error includes receiving radar pulses reflected from the ground, where pulses are emitted from the antenna of a radar system, reflected by the ground, and received by the antenna. The return pulses carry information about the ground. Measurement indices are established from radar and platform parameters, and a clutter spectrum is generated from the return pulse information. The amplitude of the clutter spectrum is measured at each of the measurement indices. Whether there is an amplitude imbalance is established in accordance with the measured amplitudes. An error estimate describing an antenna boresight error is determined if there is an amplitude imbalance.Type: GrantFiled: October 8, 2004Date of Patent: June 27, 2006Assignee: Raytheon CompanyInventor: David L. Steinbauer
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Patent number: 7053815Abstract: A radar tracking system for an anti-aircraft, missile, including angle tracking, doppler tracking and range tracking feedback loops operating on sum and difference channels. Fast fourier transform digital filters are used to provide a frequency spectrum of the sum and difference I.F. channels and detection and confirmation algorithms are employed for selecting the F.F.T. target ‘bin’. Adjacent F.F.T. bins are used to simulate a bin centered on the target frequency, shifts of the latter with target/missile acceleration causing frequency errors which are detected by a discriminator and used to control the target I.F. Confirmation of target acquisition is achieved by successive summations of the target bin power the totals being accumulated and compared with upper and lower thresholds. Confirmation and rejection results from total levels outside the thresholds while further accumulation and comparison follow the intermediate condition.Type: GrantFiled: November 30, 1982Date of Patent: May 30, 2006Assignee: Alenia Marconi Systems LimitedInventors: David William Joynson, Nigel Stansfield, Peter James MacBean
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Patent number: 7038615Abstract: A method and apparatus for estimating elevation angle when using a broad search beam such as a cosecant-squared beam is provided. The range of a target detected during a search with a broad beam covering a broad angular search area is determined. Based on the determined range, consecutive beams are transmitted at increasing search elevation angles in the broad angular search area. Echo signals of the consecutive beams are used to determine an elevation angle estimate for the target.Type: GrantFiled: October 10, 2003Date of Patent: May 2, 2006Assignee: Raytheon CompanyInventor: Eli Brookner
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Patent number: 6937186Abstract: A method for main beam alignment verification includes providing data pertaining to one or more patterns associated with an antenna, measuring power levels of a signal acquired by the antenna, and comparing the measured power levels with the data to determine whether a direction of the signal is incident upon a main beam of the antenna.Type: GrantFiled: June 22, 2004Date of Patent: August 30, 2005Assignee: The Aerospace CorporationInventors: Robert B. Dybdal, Denny D. Pidhayny
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Patent number: 6867726Abstract: An improvement in monopulse radar achieves nulling of a single mainlobe jammer and multiple sidelobe jammers while maintaining the angle measurement accuracy of the monopulse ratio by cascading a multiple sidelobe canceller and a mainlobe canceller, and imposing a mainlobe maintenance technique during the sidelobe jammer cancellation process so that the results of the sidelobe jammer cancellation process do not distort the subsequent mainlobe cancellation process. In this manner, the sidelobe jammers and the mainlobe jammer are cancelled sequentially in separate processes.Type: GrantFiled: December 16, 1991Date of Patent: March 15, 2005Assignee: Lockheed Martin CorporationInventors: Kai-Bor Yu, David Jay Murrow
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Patent number: 6853330Abstract: A radar system derives a correction for an actual boresight (311) of a radar monopulse antenna mounted on a moving platform from ? data and ? data generated with respect to an a priori known, calibrated boresight (309). The monopulse antenna (602) is coupled to a ground position measuring system (616) while acquiring data. The radar receiver acquires a ? and ? synthetic aperture map of the same radar scattering location with respect to the calibrated boresight. ? SAR data and the ? SAR data are motion compensated using the position and velocity supplied by the ground positioning system. A computer forms a ratio of the aligned ? pixels to the aligned ? pixels for each of a plurality of aligned ? pixels located near the calibrated boresight. The correction for the location of the actual boresight of the monopulse antenna is computed by an analysis of the ratio of aligned ? pixels and corresponding aligned ? pixels over the radar scattering location.Type: GrantFiled: May 13, 2004Date of Patent: February 8, 2005Assignee: Raytheon CompanyInventors: Kapriel V. Krikorian, Robert A. Rosen
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Patent number: 6853329Abstract: A monopulse radar system for detecting an azimuth depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, includes: a transmitting array antenna and a receiving array antenna each including antenna elements forming an antenna train, at least one antenna switch disposed among the elements of the transmitting array antenna and/or the receiving array antenna, and a switch controller for turning ON/OFF the antenna switch to change an aperture length of the transmitting array antenna and/or the receiving array antenna thereby changing a beam shape thereof. The antenna elements of the transmitting array antenna and the receiving array antenna are formed on a dielectric substrate. A dielectric length between the antenna train formed by the antenna elements and the antenna switch is ½ dielectric wavelength.Type: GrantFiled: March 1, 2004Date of Patent: February 8, 2005Assignee: Hitachi, Ltd.Inventors: Hiroshi Shinoda, Hiroshi Kondoh
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Patent number: 6801156Abstract: A monopulse radar system generates elevation and azimuth difference monopulse estimates of the location of targets in each range cell, where the target may be either a single or plural target, each of which is made up of multiple scattering sources. Each azimuth-elevation estimate is based on a transmitted pulse or burst at a given frequency, different from other frequencies in a set of pulses or bursts. A test statistic is generated for each set. The statistic relates to the shape in an azimuth-elevation plane of the cluster of estimates. The test statistic is compared with a threshold to decide whether a single target or plural targets exist in the range cell.Type: GrantFiled: July 25, 2003Date of Patent: October 5, 2004Assignee: Lockheed Martin CorporationInventor: Richard Wasiewicz
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Publication number: 20040164892Abstract: To realize a monopulse radar system wherein the velocity of a mobile body, distance between an obstacle and the mobile body and relative velocity can be detected and simultaneously, the direction of the obstacle can be detected, in a monopulse radar system wherein an azimuth is detected depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, an array antenna composed of plural antenna elements is used for each transmitting antenna and each receiving antenna, at least one of the transmitting antenna and the receiving antenna is provided with an antenna switch for switching an antenna beam shape to a short angle/long distance or a wide angle/short distance and a switch control device that controls the switching of the antenna switch is provided.Type: ApplicationFiled: March 1, 2004Publication date: August 26, 2004Applicant: Hitachi, Ltd.Inventors: Hiroshi Shinoda, Hiroshi Kondoh
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Patent number: 6771205Abstract: A combined defense and navigational system on a naval vessel is disclosed. The disclosed system includes a track-while-scan pulse radar which is controlled to provide either navigational information or tracking information on selected targets. Additionally, the disclosed system includes a plurality of guided missiles, each of which may be vertically launched and directed toward intercept of a selected target either by commands from the track-while-scan radar or from an active guidance system in each such missile.Type: GrantFiled: August 1, 1979Date of Patent: August 3, 2004Assignee: Raytheon CompanyInventors: David K. Barton, Benjamin L. Young
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Patent number: 6762711Abstract: In a method for detecting target objects and determining their direction, range, speed and the like for a radar device, the invention provides that at least three transmitting and receiving devices for radar beams are arranged in such a manner that their beam fields (a, b, c, d, e) form the dectection area of the radar device, and the at least three transmitting and receiving devices are activated and deactivated successively in such a manner that at least two adjacent transmitting and recieving devices are activated simultaneously.Type: GrantFiled: July 9, 2001Date of Patent: July 13, 2004Assignee: Siemens AktiengesellschaftInventor: Reiner Doerfler
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Patent number: 6753802Abstract: An electronic circuit for use in an anti-radiation missile system of the type which uses the electromagnetic transmissions of a target radar for guidance information, detects when the missile has flown into a target null and is no longer receiving energy from one of the main lobes or side lobes of the target radar transmitter. When this condition is detected, the circuit causes an attenuation in the epsilon error guidance signal to momentarily prevent guidance commands based upon the now suspect epsilon error signals from being implemented.Type: GrantFiled: October 29, 1985Date of Patent: June 22, 2004Assignee: The United States of America as represented by the Secretary of the NavyInventors: Bruce M. Heydlauff, Ralph K. Beyer
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Patent number: 6750804Abstract: 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.Type: GrantFiled: April 4, 2002Date of Patent: June 15, 2004Assignee: Raytheon CompanyInventors: Hai-Wai Chen, Harry A. Schmitt, George T. David, Dennis C. Braunreiter, Alphonso A. Samuel
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Patent number: 6750810Abstract: To realize a monopulse radar system wherein the velocity of a mobile body, distance between an obstacle and the mobile body and relative velocity can be detected and simultaneously, the direction of the obstacle can be detected, in a monopulse radar system wherein an azimuth is detected depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, an array antenna composed of plural antenna elements is used for each transmitting antenna and each receiving antenna, at least one of the transmitting antenna and the receiving antenna is provided with an antenna switch for switching an antenna beam shape to a short angle/long distance or a wide angle/short distance and a switch control device that controls the switching of the antenna switch is provided.Type: GrantFiled: March 12, 2003Date of Patent: June 15, 2004Assignee: Hitachi, Ltd.Inventors: Hiroshi Shinoda, Hiroshi Kondoh
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Patent number: 6741205Abstract: A monopulse radar system aims to correct an amplitude error and a phase error developed between receiving channels and improve the accuracy of a detected angle. To achieve the above aim, part of a transmit signal is supplied to respective channels on the receiving side through a signal transmission line for calibration. At this time, the gains of a variable phase shifter and a variable gain amplifier are adjusted so that an azimuth angle of a pseudo target, based on a signal for calibration, which is calculated by signal processing means, reaches a predetermined angle. Therefore, calibration work is simplified and an angular correction can be automated. Therefore, the present monopulse radar system is capable of coping even with variations in characteristic after product shipment due to environmental variations and time variations in parts characteristic.Type: GrantFiled: August 26, 2002Date of Patent: May 25, 2004Assignee: Hitachi, Ltd.Inventor: Toshiyuki Nagasaku
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Patent number: 6697009Abstract: A system and method for detecting a radar target of interest in the presence of radar jamming interference include a sub-array beamformer, a sum and difference beamformer, a weight calculator, a composite beamformer, and a monopulse ratio calculator. A plurality of sub-arrays is formed from antenna array element data. Respective sum and difference beams are formed for each of the plurality of sub-arrays. A single weight is formulated from the sum and difference beams, respectively. Composite sum beams are formed in accordance with the sum weights and the sum beams, and composite difference beams are formed in accordance with the difference weights and the difference beams. Composite beams are formed such that at least one null of each of the composite beams is steered toward an interference and a boresight gain of each of the composite beams is maintained.Type: GrantFiled: July 3, 2002Date of Patent: February 24, 2004Assignee: Lockheed Martin CorporationInventor: Kai Bor Yu
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Patent number: 6661366Abstract: A radar system and technique provide the capability to detect a target of interest and maintain the detection in the presence of multiple mainlobe and sidelobe jamming interference. The system and technique utilize digital beamforming to form sub-arrays for canceling jamming interference. Jamming is adaptively suppressed in the sub-arrays prior to using conventional deterministic methods to form the sum, &Sgr;, and difference, &Dgr;, beams for monopulse processing. The system and technique provide the ability to detect a target of interest, provide an undistorted monopulse ratio, m, and maintain target angle estimation, in the presence of multiple mainlobe and multiple sidelobe jammers.Type: GrantFiled: June 15, 2001Date of Patent: December 9, 2003Assignee: Lockheed Martin CorporationInventor: Kai-Bor Yu
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Publication number: 20030210177Abstract: A method for processing radar return data to determine a physical angle, in aircraft body coordinates to a target, is disclosed. The radar return data includes a phase difference between radar return data received at an ambiguous radar channel and a left radar channel, a phase difference between radar return data received at a right radar channel and an ambiguous radar channel, and a phase difference between radar return data received at a right radar channel and a left radar channel. The method includes adjusting a phase bias for the three phase differences, resolving phase ambiguities between the three phase differences to provide a signal, and filtering the signal to provide a physical angle to the target in aircraft body coordinates.Type: ApplicationFiled: May 13, 2002Publication date: November 13, 2003Inventors: James R. Hager, Lavell Jordan, Todd R. Burlet
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Publication number: 20030164791Abstract: To realize a monopulse radar system wherein the velocity of a mobile body, distance between an obstacle and the mobile body and relative velocity can be detected and simultaneously, the direction of the obstacle can be detected, in a monopulse radar system wherein an azimuth is detected depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, an array antenna composed of plural antenna elements is used for each transmitting antenna and each receiving antenna, at least one of the transmitting antenna and the receiving antenna is provided with an antenna switch for switching an antenna beam shape to a short angle/long distance or a wide angle/short distance and a switch control device that controls the switching of the antenna switch is provided.Type: ApplicationFiled: March 12, 2003Publication date: September 4, 2003Applicant: Hitachi, Ltd.Inventors: Hiroshi Shinoda, Hiroshi Kondoh
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Publication number: 20030160718Abstract: A monopulse radar system aims to correct an amplitude error and a phase error developed between receiving channels and improve the accuracy of a detected angle.Type: ApplicationFiled: August 26, 2002Publication date: August 28, 2003Applicant: Hitachi, Ltd.Inventor: Toshiyuki Nagasaku
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Patent number: 6608584Abstract: A method and bistatic synthetic aperture radar (SAR) imaging system generate an image of a target area without knowledge of the position or velocity of the illuminator. The system includes an illuminator to illuminate a target area with a null-monopulse radiation pattern interleaved with a sum radiation pattern. The illuminator adjusts the phase terms of the sum radiation pattern to maintain a static electromagnetic field pattern at the target area. A receiver receives the radiation patterns reflected from the target area and generates phase compensation terms by correlating a measured electromagnetic vector field with the known static electromagnetic vector field. The phase compensation terms are used to generate an image of the target area.Type: GrantFiled: February 12, 2002Date of Patent: August 19, 2003Assignee: Raytheon CompanyInventor: David A. Faulkner
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Patent number: 6603421Abstract: A combined defense and navigational system on a naval vessel is disclosed. The disclosed system includes a track-while-scan pulse radar which is controlled to provide either navigational information or tracking information on selected targets. Additionally, the disclosed system includes a plurality of guided missiles, each of which may be vertically launched and directed toward intercept of a selected target either by commands from the track-while-scan radar or from an active guidance system in each such missile.Type: GrantFiled: July 28, 1977Date of Patent: August 5, 2003Assignee: Raytheon CompanyInventors: George W. Schiff, David K. Barton, Robert E. Millett, Carroll D. Phillips
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Publication number: 20030117314Abstract: 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.Type: ApplicationFiled: August 16, 2001Publication date: June 26, 2003Applicant: LOCKHEED MARTIN CORPORATIONInventor: Kai-Bor Yu
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Publication number: 20030112172Abstract: To realize a monopulse radar system wherein the velocity of a mobile body, distance between an obstacle and the mobile body and relative velocity can be detected and simultaneously, the direction of the obstacle can be detected, in a monopulse radar system wherein an azimuth is detected depending upon amplitude difference or phase difference between signals respectively received by plural receiving antennas, an array antenna composed of plural antenna elements is used for each transmitting antenna and each receiving antenna, at least one of the transmitting antenna and the receiving antenna is provided with an antenna switch for switching an antenna beam shape to a short angle/long distance or a wide angle/short distance and a switch control device that controls the switching of the antenna switch is provided.Type: ApplicationFiled: February 27, 2002Publication date: June 19, 2003Applicant: Hitachi, Ltd.Inventors: Hiroshi Shinoda, Hiroshi Kondoh
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Patent number: 6568629Abstract: A process and a device for electromagnetic guidance of a craft, applied in particular to the tracking of targets. Guidance is carried out with respect to the axis of the beam of a monopulse antenna, by coding in space of the beam. The coding is carried out by appropriate modulation of the signals radiated by a sum pattern and difference pattern. A receiver is disposed in the craft to make it possible to determine the position of the craft with respect to the antenna radiation patterns, and hence its position with respect to the axis of the antenna, the determination of this position being performed by demodulating the signals captured by the receiver. The process and device may be applied in particular in respect of the guidance of any number of missiles or intelligent munitions, for example in the tracking of targets.Type: GrantFiled: November 19, 2001Date of Patent: May 27, 2003Assignee: ThalesInventors: Jacques Perrin, Sylvain Baudas
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Patent number: 6567034Abstract: In a radar system, sampled aperture data are received from an antenna array. The sampled aperture data include data that do not correspond to echo returns from a beam transmitted by the antenna. A covariance matrix is generating using the sampled aperture data. An eigenvalue decomposition is performed on the covariance matrix. A direction of arrival is determined from which at least one jammer is transmitting a signal included in the sampled aperture data, based on the eigenvalue decomposition.Type: GrantFiled: September 5, 2001Date of Patent: May 20, 2003Assignee: Lockheed Martin CorporationInventor: Kai-Bor Yu
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Patent number: 6538597Abstract: A radar system including a blanker and a sidelobe canceler is described including an open loop nulling circuit for introducing one or more nulls in the main beam and a blanker beam. With this arrangement, the blanker can be operated even in the presence of strong sidelobe jamming without the conventional problems attributable to noise amplification. Also described is an antenna configuration for implementing the open loop nulling, including a pair of orthogonal linear arrays. One of the arrays is omnidirectional in azimuth and directional in elevation and the other array is omnidirectional in elevation and directional in azimuth in order to point the main and blanker beams in the direction of jammers. In one embodiment, the radar system further includes a spoofer and the crossed linear arrays process the spoofer signals on transmit and process blanker signals on receive.Type: GrantFiled: February 14, 2000Date of Patent: March 25, 2003Assignee: Raytheon CompanyInventor: Fritz Steudel
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Publication number: 20030020646Abstract: A radar system and technique provide the capability to detect a target of interest and maintain the detection in the presence of multiple mainlobe and sidelobe jamming interference. The system and technique utilize the versatility of digital beamforming to form sub-arrays for canceling jamming interference. Jamming is adaptively suppressed in the sub-arrays prior to using conventional deterministic methods to form the sum, &Sgr;, and difference, &Dgr;, beams for monopulse processing. The system and technique provide the ability to detect a target of interest, provide an undistorted monopulse ratio, m, and maintain target angle estimation, in the presence of multiple mainlobe and multiple sidelobe jammers. Further, this system and technique are not constrained by requiring a priori knowledge of the jamming interference.Type: ApplicationFiled: June 15, 2001Publication date: January 30, 2003Inventor: Kai-Bor Yu
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Patent number: 6498582Abstract: A passive MMIC monopulse comparator includes a plurality of lumped element hybrids having pi and T filter structures. In one embodiment, a first hybrid receives first and second downcoverted signals and provides a first output signal to a third hybrid and second output signal to a fourth hybrid. A second hybrid receives third and fourth downconverted signals and provides respective third and fourth output signals to the third and fourth hybrids. The third hybrid provides sum and elevation channel signals and the fourth hybrid provides azimuth and G channel signals.Type: GrantFiled: August 8, 2000Date of Patent: December 24, 2002Assignee: Raytheon CompanyInventors: Anthony Sweeney, Mark A. Hebeisen, Andrew B. Forbes, Ray Gingras, John Toth, Michael J. Delcheccolo, George La Fave, Joseph Licciardello
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Publication number: 20020190892Abstract: A circuit (100) for performing base 10 logarithmic calculations of a binary signal in a digital system that optimizes accuracy of the calculation. The circuit comprises a priority encoder (108) for determining a most significant bit position of the binary number, with the most significant bit representing a base 2 logarithmic integer component of the input binary signal. A decimal selector (120) selects a predetermined number of bits to follow the base 2 logarithmic integer component determined by the priority encoder, with the predetermined number of bits representing a base 2 logarithmic fractional component following the integer component of the input binary signal. An adder (116) combines the integer component with the fractional component to thereby output a base 2 logarithmic value of the input binary signal. A multiplier (132) divides the base 2 logarithmic value of the input binary signal by a base 2 logarithmic value of 10 to thereby output a base 10 logarithmic value of the input binary signal.Type: ApplicationFiled: March 19, 2002Publication date: December 19, 2002Inventor: Brian L. Hallse
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Patent number: 6476760Abstract: A method and a radar sensor for determining an elevation angle error of a multibeam radar sensor are described. In order to detect an elevation angle of the multibeam radar system with respect to a predefined target, a plurality of laterally arranged cutting planes at a predefined distance are formed. The values of the corresponding antenna diagrams in each plane are stored in a suitable form, for example, normalized and in a parametric form taking into account the elevation angle &agr;. In order to reduce the size of the memory, it is sufficient to store one symmetry half for reasons of symmetry if additional information, for example, road clutter values are added, so that the upward or downward direction of the angle can be recognized. By comparing the measured echo values obtained by normalization and application of a quality factor, a corresponding elevation angle &agr; is obtained for each cutting plane.Type: GrantFiled: October 11, 2001Date of Patent: November 5, 2002Assignee: Robert Bosch GmbHInventors: Klaus Winter, Klaus-Peter Wagner, Sonja Eder, Herbert Olbrich, Jörg Schneemann
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Patent number: 6456238Abstract: An antenna array system with dynamic signal routing to a set of receivers. A monopulse electronically scanned antenna (ESA) has a plurality of antenna elements divided into subarrays. ESA beam steering phase shifters are associated with the respective subarrays of antenna elements, such that the output signals from the respective antenna elements associated with the respective quadrants are phase shifted and summed to provide respective subarray signals. A monopulse network responsive to the subarray signals provides monopulse outputs to a set of receivers. A beam steering controller provides phase shift commands to the ESA phase shifters to set the phase shift associated with the respective phase shifters of the subarrays. The controller commands the ESA phase shifters to modulate the phase shift of selected quadrants.Type: GrantFiled: May 15, 2001Date of Patent: September 24, 2002Assignee: Raytheon CompanyInventor: William P. Posey