Adaptive digital sub-array beamforming and deterministic sum and difference beamforming, with jamming cancellation and monopulse ratio preservation
AssigneeLockheed Martin Corporation
InventorKai-Bor Yu
Life of this patent
Estimating the term…
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, Σ, and difference, Δ, 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.
Claims15
A method for detecting a radar target of interest in the presence of multiple radar jamming interference sources, said method comprising the steps of:
- forming a plurality of sub-arrays from an antenna array;
- digitally beamforming sub-array data from the plurality of sub-arrays and generating quadrant sub-array beams, each with a respective sub-array beam pattern for each of said plurality of sub-arrays, and each quadrant sub-array beam having nulls at identical null positions, said sub-array beams formed having a constraint of maintaining a given boresight gain of each said quadrant sub-array beam;
- steering the nulls associated with the quadrant sub-array beams in directions associated with the sources of interference;
- determining sum and difference beams from said plurality of sub-array beams for detecting said target of interest;
- determining a monopulse ratio based on the sum and difference beams;
- and estimating an angle of arrival of the target using the monopulse ratio.
A radar system for detecting a radar target of interest in the presence of multiple sources of interference, said system comprising:
- an antenna array for providing antenna array element data;
- a summer for forming a plurality of sub-arrays from said antenna array element data;
- a quadrant sub-array beamformer for digitally forming quadrant sub-array beams from said plurality of sub-arrays;
- wherein each quadrant sub-array beam has a respective beam pattern including nulls at identical null positions, wherein the nulls of each sub-array beam pattern are steered toward the sources of interference;
- a monopulse summer for forming sum beams from said quadrant sub-array beams for detecting said target of interest.
A computer readable medium having embodied thereon a computer program for detecting a radar target of interest in the presence of multiple sources of interference, the computer readable program comprising:
- means for causing a processor to form a plurality of sub-arrays from an antenna array;
- means for causing said processor to adaptively form a respective quadrant sub-array beam for each of said plurality of sub-arrays, wherein at least one null of each sub-array beam is steered toward a respective one of the sources of interference and a boresight gain of each sub-array beam pattern is maintained;
- means for causing said processor to determine sum and difference beams from said sub-array beams;
- and
- means for causing said processor to determine at least one monopulse ratio from said sum and difference beams for detecting a radar target of interest and for estimating an angle of arrival of said target of interest.
A method for detecting a radar target of interest in the presence of multiple radar jamming interference sources, said method comprising the steps of:
- forming a plurality of sub-arrays from an antenna array;
- digitally beamforming sub-array data from the plurality of sub-arrays and adaptively generating four quadrant sub-array beams for each of the plurality of sub-arrays using all of the sub-array data elements, each quadrant sub-array beam having a respective sub-array beam pattern and each quadrant sub-array beam having identical nulls and constrained with a given boresight gain;
- steering the nulls associated with the quadrant sub-array beams in directions associated with each of the sources of interference;
- determining sum and difference beams from said plurality of sub-array beams for detecting said target of interest;
- determining a monopulse ratio based on the sum and difference beams;
- and
- estimating an angle of arrival of the target using the monopulse ratio.
Dependencies are inferred from the claim text.