WIDEBAND ACTIVE SONAR BEAMFORMING

BEAMFORMING METHODS IN WHICH THE FAST CONVOLUTION TECHNIQUE IS APPLIED TO EXECUTE MULTICHANNEL TIME DELAY FIR INTERPOLATION FILTERING IS THE SUBJECT OF THIS PROPOSAL. THE METHOD OFFERS THE POTENTIAL FOR EXECUTING CERTAIN PRIOR AND POST BEAMFORMING FIR FILTER-ING OPERATIONS WITHIN THE BEAMFORMER PROCESSING TO ENHANCE OVERALL SYSTEM COMPUTATIONAL EFFICIENCY. TWO FAST CONVOLUTION METHODS BASED ON DIFFERENT APPROACHES TO SYNTHESIZING THE DELAY INTERPOLATION FILTERS ARE PROPOSED FOR PHASE I TRADE-OFF STUDIES. ONE METHOD OFFERS THE POTENTIAL FOR THE DEVELOPMENT OF A PRACTICAL BEAMFORMING STRUCTURE WHICH CAN BE PROGRAMMED TO MAXIMIZE PERFORMANCE IN A WIDE RANGE OF NOISE SOURCE DISTRIBUTIONS. THE METHOD SHOULD PROVIDE FOR ADAPTIVE REJECTION OF SPATIALLY DISCRETE NOISE INTERFERENCE IN THE NEAR TERM. IT ALSO PROVIDES FOR A PRACTICAL SYSTEM TO ADAPTIVELY MAXIMIZE GAIN IN A VARIETY OF COMPLEX, CORRELATED NOISE FIELDS.