SELF-SURVEY OF DISTRIBUTED THINNED PHASED ARRAYS

WE PROPOSE TO CONDUCT A STUDY LEADING TO THE EXPERIMENTAL COMPARISON OF THE PERFORMANCE OF SELF-SURVEY TECHNIQUES WITH ADAPTIVE BEAMFORMING IN ORDER TO COHERE LARGE AND DISTRIBUTED PHASED ARRAYS. PHASE I WILL (1) ANALYTICALLY COMPARE THE TWO APPROACHES, (2) ASSESS EQUIPMENT REQUIREMENTS, (3) ANALYZE PHASE ERRORS, (4) EVALUATE PREDICTED PERFORMANCE, AND (5) DESIGN AN EXPERIMENT TO COMPARATIVELY DEMONSTRATE THE TWO APPROACHES TO COHERING THE ARRAY. THE PROPOSED EXPERIMENT (TO BE PERFORMED UNDER PHASE II OF THIS PROGRAM) WILL UTILIZE EQUIPMENT BEING BUILT BY INTERSPEC UNDER A CURRENT PHASE II SBIR CONTRACT TO RADC/EEA, HANSCOM. THE EXPERIMENT REQUIRES MINIMAL HARDWARE CHANGES. A NUMBER OF OFF-THE-SHELF LASER SURVEYING INSTRUMENTS (A MINIMUM OF ONE AND A MAXIMUM OF THREE) SHALL BE ADDED TO THE EXISTING 3-ELEMENT DISTRIBUTED ARRAY RADAR. THE EXPERIMENT SHALL QUANTIFY REQUIREMENTS FOR COHERING A LARGE OR DISTRIBUTED ARRAY RADAR USING (1) SELF-SURVEY ALONE, (2) ADAPTIVE-BEAMFORMING ALONE, AND (3) A HYBRID SELF-SURVEY/ADAPTIVE BEAMFORMING TECHNIQUE. THE NEW HYBRID TECHNIQUE, TO BE DEVELOPED UNDER THIS PHASE I EFFORT, USES A COARSE SELF-SURVEY SYSTEM TO ESTABLISH APPROXIMATE ELEMENT POSITONS AND IMPROVES THE ESTIMATES ADAPTIVELY USING CLUTTER RETURNS. THEN ADAPTIVE BEAMFORMING IS APPLIED. THE ROBUST BEAM PRODUCED BY ADAPTIVE BEAMFORMING CAN BE SCANNED OVER WIDE ANGULAR REGIONS A MINIMAL SELF-SURVEY SYSTEM.