Abstract: A method and apparatus for managing an antenna. A current radiation pattern is identified for the antenna using initial coefficients for a modulation function for the antenna. A first constraint is applied to the current radiation pattern to form a modified radiation pattern. New coefficients for the modulation function are identified as coefficients for which a difference between a radiation pattern for the antenna generated using the coefficients and the modified radiation pattern is reduced. A second constraint is applied to a set of coefficients in the new coefficients to form modified coefficients for the modulation function. The steps of applying the first constraint, identifying the new coefficients for the modulation function, and applying the second constraint are iterated until a new radiation pattern based on the modified coefficients for the modulation function meets the first constraint.

Abstract: A method for electronically compensating for quantization errors and bit toggle errors with phase shifters. A new bit state for a phase shifter associated with an element is identified based on a desired phase shift for the element. The new bit state minimizes a quantization error and a bit toggle error between the desired phase shift for the element and an actual phase shift that results when a current bit state is switched to the new bit state. A command is sent to the phase shifter to switch from the current bit state to the new bit state.

Abstract: A system and method for increasing the effective angular resolution of a multi-function phased array radar system is provided. The system is operative to simultaneously transmit a plurality of overlapping sub-beams covering a representative central beam. A de-convolution process is applied to received return signals. The process includes determining the reflectivity within sub-beamwidth resolution cells defined by the overlapping sub-beams. Generated sub-beamwidth data provides the radar system with an effective angular resolution beyond that of any single transmitted beam.

Abstract: A method and apparatus for identifying locations of objects. A portion of a sum signal corresponding to angular locations and velocities with respect to a sensor system that are different from a selected angular location and a selected velocity with respect to the sensor system, respectively, is modified to form a set of modified sum signals. A portion of a difference signal corresponding to the angular locations and the velocities with respect to the sensor system that are different from the selected angular location and the selected velocity with respect to the sensor system, respectively, is modified to form a modified difference signal. An angular location of a target object is identified with respect to the sensor system using the set of modified sum signals and the modified difference signal.

Abstract: A method and apparatus for identifying locations of objects. A portion of a sum signal corresponding to angular locations and velocities with respect to a sensor system that are different from a selected angular location and a selected velocity with respect to the sensor system, respectively, is modified to form a set of modified sum signals. A portion of a difference signal corresponding to the angular locations and the velocities with respect to the sensor system that are different from the selected angular location and the selected velocity with respect to the sensor system, respectively, is modified to form a modified difference signal. An angular location of a target object is identified with respect to the sensor system using the set of modified sum signals and the modified difference signal.

Abstract: A system and method for increasing the effective angular resolution of a multi-function phased array radar system is provided. The system is operative to simultaneously transmit a plurality of overlapping sub-beams covering a representative central beam. A de-convolution process is applied to received return signals. The process includes determining the reflectivity within sub-beamwidth resolution cells defined by the overlapping sub-beams. Generated sub-beamwidth data provides the radar system with an effective angular resolution beyond that of any single transmitted beam.

Abstract: A method for determining target angles based on data received from a monopulse radar array antenna includes receiving from a beamformer that generates beams from signals generated by the monopulse radar antenna signals having data indicative of a sum beam, an azimuth difference beam, an elevation difference beam, and a delta-delta beam; based on the received signals, determining by the processor an azimuth monopulse ratio, an elevation monopulse ratio, a first complementary monopulse ratio based on the ratio of the delta-delta beam to the delta elevation beam, and a second complementary monopulse ratio based on the ratio of the delta-delta beam to the delta azimuth beam; determining an azimuth angle by the processor based on the azimuth monopulse ratio and the first complementary monopulse ratio; determining an elevation angle by the processor based on the elevation monopulse ratio and the second complementary monopulse ratio; providing an output signal indicative of the azimuth angle; and providing an output

Abstract: A method for determining target angles based on data received from a monopulse radar array antenna includes receiving from a beamformer that generates beams from signals generated by the monopulse radar antenna signals having data indicative of a sum beam, an azimuth difference beam, an elevation difference beam, and a delta-delta beam; based on the received signals, determining by the processor an azimuth monopulse ratio, an elevation monopulse ratio, a first complementary monopulse ratio based on the ratio of the delta-delta beam to the delta elevation beam, and a second complementary monopulse ratio based on the ratio of the delta-delta beam to the delta azimuth beam; determining an azimuth angle by the processor based on the azimuth monopulse ratio and the first complementary monopulse ratio; determining an elevation angle by the processor based on the elevation monopulse ratio and the second complementary monopulse ratio; providing an output signal indicative of the azimuth angle; and providing an output

Abstract: A method for target detection and angle estimation in a radar system includes receiving a signal from a radar array; based on the received signal, performing monopulse beamforming to obtain one or more monopulse beams; based on the monopulse beams, determining monopulse ratios; using maximum likelihood estimation based on the determined monopulse ratios to determine a monopulse ratio estimate corresponding to a maximum of a likelihood function; accessing a table correlating monopulse ratio estimates and target angle values and determining from the table an estimated target angle; accessing a complex target amplitude corresponding to the estimated target angle, comparing the complex target amplitude to a threshold; and if, based on the step of comparing, the target amplitude exceeds the threshold, providing an output signal indicative of target detection and the estimated target angle.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method and system for are provided for detecting one or more radar targets of interest in the presence of jamming signals. A plurality of sub-arrays are formed from an antenna array. Sub-array beams are adaptively formed so as to point one or more nulls in one or more respective directions corresponding to one or more jammers. A super-resolution technique is applied to determine a count of the one or more radar targets and to determine the corresponding direction of arrival.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A method and system for are provided for detecting one or more radar targets of interest in the presence of jamming signals. A plurality of sub-arrays are formed from an antenna array. Sub-array beams are adaptively formed so as to point one or more nulls in one or more respective directions corresponding to one or more jammers. A super-resolution technique is applied to determine a count of the one or more radar targets and to determine the corresponding direction of arrival.

Abstract: 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.

Abstract: A system identifies a number of targets within a main beam of an antenna array that transmits the main beam and receives echo returns from the main beam. A covariance matrix is generated using the echo returns. The presence of at least one target within a single range cell is detected. A plurality of consecutive pulses are transmitted in a direction of the single range cell within a sufficiently short period that the at least one target remains within the single range cell while the plurality of consecutive pulses are transmitted. An echo signal is sampled from each of the plurality of pulses. An updated covariance matrix is estimated each time the echo signal is sampled. An eigenvalue decomposition is updated each time the covariance matrix is updated. The number of targets in the single range cell is estimated, based on the updated eigenvalue decomposition.

Abstract: A radar monopulse signal receiving system according to an aspect of the invention provides sum (&Sgr;) and a single difference (&Dgr;) beam outputs from the beamformer. This is accomplished by encoding the information relating to the azimuth and elevation difference beams onto a single complex number. By comparison with some prior-art arrangements, the number of channels required for processing the signals is reduced. Near the end of the monopulse processing, the quotient is taken of complex number divided by the sum beam information, which directly produces a complex monopulse ratio m=mA+jmE. The azimuth and elevation monopulse ratios are represented by mA and mE, respectively.