Accession Number : ADD018262

Title :   Preprocessor and Adaptive Beamformer for Active Signals of Arbitrary Waveform.

Descriptive Note : Patent, Filed 16 Mar 95, patented 2 Jul 96,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Lockwood, James C

Report Date : 02 Jul 1996

Pagination or Media Count : 17

Abstract : A pre-processor and adaptive beamformer processes an echo received by an array of receiving elements from a distant target from a transmitted signal having an arbitrary waveform capable of being represented as a complex modulation of a carrier frequency. Time blocks are formed from each element output represented by a series of time windows extending from an initial time appropriate to the arrival time of the echo to a final time appropriate to the time block. A correlation is performed of each time block with a replica of the transmitted signal. The correlation products are aligned with respect to time difference to within one sample period. The beamformer further aligns the correlation products with respect to time difference to substantially the same phase for each steering direction. Covariance estimates are formed using techniques of spatial averaging to generate adaptive weights optimized to suppress interfering signals without requiring the use of time averaging.

Descriptors :   *BEAM FORMING, *SONAR SOUND ANALYZERS, *PATENTS, SPATIAL DISTRIBUTION, FREQUENCY MODULATION, CORRELATION, ADAPTIVE SYSTEMS, COVARIANCE, CARRIER FREQUENCIES, SONAR ARRAYS

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE