DESIGN AND DEVELOPMENT OF AN ADAPTIVE VEHICULAR NOISE SUPPRESSION SYSTEM (ANVSS)

THE DETECTION, CLASSIFICATION AND IDENTIFICATION RANGE OF ACOUSTIC SENSORS IS INVERSELY PROPORTIONAL TO THE BACKGROUND NOISE LEVEL ALL OTHER FACTORS BEING HELD CONSTANT. BACKGROUND NOISE IS GENERATED BY A WHOLE HOST OF ENVIRONMENTAL CONDITIONS TO INCLUDE MAN-MADE BATTLEFIELD NOISES, NOISE GENERATED BY THE VEHICLE ON WHICH THE ACOUSTIC TRANSDUCERS ARE MOUNTED, AND WIND (WIND BLOWING ACROSS THE TRANSDUCER AND WIND CAUSING LEAVES TO RUSTLE, ETC.). DEPLOYMENT CONCEPTS TO MITIGATE THE EFFECTS OF BACKGROUND NOISE INCLUDE DEPLOYMENT IN "QUIET" AREAS AWAY FROM NOISE MAKERS AND/OR DEPLOYMENT OF THE SENSORS CLOSE TO THE INTENDED TARGET (E.G., FORWARD DEPLOYED EXPENDABLES - DOES NOT REDUCE NOISE BUT INCREASES SIGNAL LEVEL). THESE DEPLOYMENT CONCEPTS WILL WORK WELL IN A STATIC OR SLOW MOVING TACTICAL ENVIRONMENT BUT ARE CERTAINLY NOT SUITABLE FOR AIR LAND BATTLE FUTURE TYPE WARFARE AS DEMONSTRATED IN THE 100 HOUR WAR WITH IRAQ. THE TECHNICAL OBJECTIVE OF PHASE I WILL BE TO DESIGN AN ADAPTIVE VEHICULAR NOISE SUPPRESSION SYSTEM (AVNSS) AND TO DEVELOP THE SIGNAL PROCESSING ALGORITHMS THAT CAN IDENTIFY AND NULL OUT VEHICLE RELATED NOISE SOURCES TO THE DEGREE NECESSARY TO ACHIEVE OPERATIONALLY USEFUL DETECTION RANGES WHEN THE VEHICLE IS MOVING AT TACTICAL SPEEDS. THE BASELINE DESIGN WILL BE BASED UPON MULTI-REFERENCE ANC AND ADAPTIVE BEAM-FORMING ALGORITHMS DEVELOPED UNDER PREVIOUS CONTRACTS. THE ALGORITHMS WILL BE MODIFIED TO ENHANCE PERFORMANCE WHEN THE SENSOR PLATFORM IS MOVING. THE ALGORITHMS WILL BE COMBINED WITH A NEW ALGORITHM TO BE DEVELOPED UNDER THIS PROPOSED EFFORT: MULTI-POLE SUB-ARRAY BEAM FORMING (MP/SA).