CLUTTER REDUCTION AND RESOLUTION ENHANCEMENT TECHNIQUES FOR FOLIAGE PENETRATING SYNTHETIC APERTURE RADAR SYSTEMS

THIS RESEARCH PROPOSAL IS AIMED AT PRELIMINARY INVESTIGATION AND FEASIBILITY ASSESSMENT OF SIGNAL PROCESSING TECHNIQUES FOR IMPROVING THE SIGNAL-TO-CLUTTER RATIO IN FOLIAGE PENETRATION SYNTHETIC APERTURE RADAR (SAR) DATA, BASED ON ADAPTIVE CROSS-MODELING OF THE COMPETING CLUTTER THROUGH THE USE OF MULTIPLE RADAR FREQUENCIES. THE ADAPTIVE CROSS-MODELING APPROACH SEEKS TO ESTIMATE THE CLUTTER RETURNS IN LOW FREQUENCY, LOW RESOLUTION FOLIAGE PENETRATING SAR DATA, BY USING HIGHER RESOLUTION SAR IMAGERY OF THE SAME GROUND AREA COLLECTED AT A HIGHER, NON-FOLIAGE-PENETRATING, RADAR FREQUENCY. OUR INITIAL PROPOSED TECHNIQUE OPERATES ON COMPLEX IMAGERY (AMPLITUDE AND PHASE), AND MODELS THE CLUTTER RETURNS IN EACH (LARGE) RESOLUTION CELL OF THE LOW FREQUENCY IMAGE AS A SCALED AND BLURRED VERSION OF THE MEASURED CLUTTER DATA IN A CONTIGUOUS GROUPING OF (SMALLER) RESOLUTION CELLS OF THE HIGH FREQUENCY DATA, COVERING THE SAME GROUND PATCH. SCALING OF THE CLUTTER RETURNS FROM ONE FREQUENCY TO THE OTHER IS DEPENDENT ON CLUTTER TYPE, WHICH IN TURN IS ASSESSED USING IMAGE PROCESSING ALGORITHMS OF THE TYPE DEVELOPED FOR TERRAIN CLASSIFICATION, AND MODIFIED FOR APPLICATION TO SAR DATA. THE PHASE I PROPOSAL INCLUDES DEVELOPMENT OF A MULTI-FREQUENCY SAR SIMULATION CAPABILITY TO SUPPORT PRELIMINARY ALGORITHM DEVELOPMENT, PLUS IMPLEMENTATION AND PRELIMINARY FEASIBILITY ASSESSMENT OF THE BASIC CROSS-MODELING APPROACH. REFINEMENT OF THE CLUTTER SUPPRESSION ALGORITHMS AND THE DEVELOPMENT AND EVALUATION OF TARGET DETECTION AND IDENTIFICATION TECHNIQUES APPROPRIATE TO THE CLUTTER-REDUCED DATA ARE PROJECTED FOR PHASE II, PENDING SUCCESSFUL COMPLETION OF THE PHASE I TECHNICAL OBJECTIVES.