X-BAND, AIR-TO-AIR RADAR SIDELOBE CLUTTER MITIGATION THROUGH ADAPTIVE PROCESSING X-BAND, AIR-TO-AIR RADAR SIDELOBE CLUTTER MITIGATION THROUGH ADAPTIVE PROCESSING

AN ADAPTIVE ARRAY SIGNAL PROCESSOR CAPABLE OF ADAPTIVELY NULLING MULTIPE SIDELOBE JAMMERS AND SIDELOBE DISTRIBUTED AND DISCRETE GROUND CLUTTER RETURNES COMPETING WITH THE TARGET RETURN, IN AI-LOW OBSERVABLE TARGET DETECTING MEDIUM-PRF RADARS IS THE SUBJECT OF A DESIGN STUDY. THE ASI-DEVELOPED AIRBORNE RADAR ADAPTIVE ARRAY SIMULATION TEST BED (IMPLEMENTED IN A PC-286 COMPUTER) IS PROPOSED TO BE USED DURING THE PHASE I PROGRAM FOR EVALUATION A NUMBER OF CANDIATEADAPTIVE ARRAY SIGNAL PROCESSORS BY 'FLYING' THE AIRBORNE RADAR INCORPORATING EACH PROCESSOR IN THE MODDELLED JAMMING AND GORUND CLUTTER ENVIRONMENT. THE CANDIDATE CONFIGURATIONS INCLUDE SPACE-TIME ADAPTIVE PROCESSORS (STAP) EFFECTING THE SIDELOBE JAMMER NULLING IN A SINGLE PROCESSOR; AND ALSO TWO-STAGE PROCESSORS - MOTIVATED BY DIMENSIONALITY REDUCTION GOALSPERFORMING THE MULTIPLE SIDELOBE JAMMER NULLING FUNCTION IN A FIRSTSTAGE SIDELOBE CANCELLER CONFIGUREATION, AND ALLOCATING THE SECOND STAGE FOR THE SIDELOBE NULLING FUNCITON IMPLEMENTED WITH EITHER A STAP OR SPATIAL-ONLY PROCESSOR ADAPTIING IN DOPPLER FILTER SPACE. THE FORMIDABLE DESIGN PROBLEM OF ABOIDING THE 'CONTAMINATING' SIDELOBE GROUND CLUTTER IN THEFIRST STAGE SLC IS DISCUSSED. PERFORMING BOTH FUNCTIONS IN A SINGLE STAP PROCESSOR IS NOTED TO OVERCOME THIS DIFFICULTY. CONFIGURATIONS INVOLVING BOTH APERTURE AND BEAM PACE ADPATATION WILL BE EVALUATED. IMPLEMENTATION CONSIDERATIONS INCLUDE THE USE OF SUBBANDING, AND SYSTOLIC ARRAYS EMPLOYING THE GRAMM-SCHMIDT ORTHOGONALIZING NODE.