ANGLE TRACKING AND SCATTERED JAMMING CANCELLATION IN ADAPTIVE DIGITAL ARRAY RADARS

ADAPTIVE DIGITAL ARRAY PROCESSING IN AIRBORNE RADARS CAN PROVIDE A MAJOR IMPROVEMENT IN TARGET DETECTABILITY BY ADAPTIVELY SUPPRESSING CLUTTER AND JAMMING. THE EFFECTIVENESS OF THIS SPACETIME ADAPTIVE PROCESSING HAS BEEN DEMONSTRATED BY DETAILED SIMULATION AT ASI. RECENTLY, ARRAY RADAR FLIGHT TEST DATA WAS USED TO VERIFY THE PERFORMANCE OF ADAPTIVE RADAR. THE PROPOSED STUDY WILL EXTEND THE SIMULATION OF SPACE-TIME ADAPTIVE RADAR TO ANGLE TRACKING AND TO THE CANCELLATION OF SCATTERED JAMMING. ONE OBJECTIVE OF THE EFFORT IS THE DEVELOPMENT OF ALGORITHMS FOR ANGLE MEASUREMENT IN ADAPTIVE ARRAY RADARS WHERE THE ANTENNA PATTERNS ARE ADAPTED IN RESPONSE TO CLUTTER AND JAMMING. THE PATTERN DISTORTIONS ADD ERRORS TO CONVENTIONAL ANGLE TRACKERS, SUCH AS MONOPULSE. A MAXIMUM LIKELIHOOD ANGLE ESTIMATOR FOR THESE SYSTEMS WILL BE SIMULATED USING MODIFIED VERSIONS OF THE EXISTING ASI PROGRAMS. THE SECOND PROGRAM OBJECTIVE IS THE DEVELOPMENT AND SIMULATION OF ADAPTIVE ARRAY ALGORITHMS FOR SUPPRESSING SCATTERED JAMMING IN ADDITION TO CLUTTER AND DIRECT JAMMING. SCATTERED JAMMING IS A POSSIBLE LIMITATION IN SYSTEMS WHERE DIRECT LINE-OF-SIGHT JAMMING IS NULLED ADAPTIVELY TO A LOW LEVEL. JAMMING SCATTERED INTO THE MAIN BEAM OF A RADAR CANNOT BE NULLED IN ANGLE. A METHOD OF CANCELLING THIS SCATTERED JAMMING IS DESCRIBED IN THE PROPOSAL. THE ANGLE TRACKING TECHNIQUES DEVELOPED DURING THE PROGRAM WILL PROVIDE AN IMPORTANT CAPABILITY FOR MISSILE SEEKERS AND AIRBORNE RADARS OPERATING IN CLUTTER AND JAMMING. SCATTERED JAMMING SUPPRESSION IS ALSO IMPORTANT FOR FUTURE ADAPTIVE RADARS.