Accession Number : ADA309720

Title :   Evaluation of the Dominant Mode Rejection Beamformer.

Descriptive Note : Technical rept.,

Corporate Author : TEXAS UNIV AT AUSTIN APPLIED RESEARCH LABS

Personal Author(s) : Messerschmitt, Tina R.

PDF Url : ADA309720

Report Date : 11 JAN 1996

Pagination or Media Count : 109

Abstract : Increasing the number of hydrophones in an array should increase beamformer performance. However, when the number of hydrophones is large, integration times must be long enough to give accurate cross spectral matrix (CSM) estimates, but short enough so that the dynamic behavior of the noise described by the CSM is captured. The dominant mode rejection (DMR) beamformer calculates adaptive weights based on a reduced rank CSM estimate, where the CSM estimate is formed with a subset of the largest eigenvalues and their eigenvectors. Since the largest eigenvalue/eigenvector pairs are estimated rapidly, the integration time required is reduced. The purpose of this study was to examine the DMR beamformer performance using several bottom mounted horizontal line arrays, in both deep and shallow water environments. The data were processed with two fully adaptive beamformers and the DMR beamformer. The DMR beamformer showed less output power bias at shorter integration times and also showed better performance than the fully adaptive beamformers when using arrays with larger numbers of hydrophones. Thus, in highly dynamic noise environments, the DMR beamformer may be a more appropriate implementation to use for passive sonar detection systems.

Descriptors :   *BEAM FORMING, *SONAR ARRAYS, DYNAMIC RESPONSE, EIGENVECTORS, EIGENVALUES, WEIGHTING FUNCTIONS, SHALLOW WATER, ADAPTIVE SYSTEMS, HYDROPHONES, BIAS, CONFIGURATION MANAGEMENT, REJECTION, NOISE(SOUND), RANK ORDER STATISTICS, PASSIVE SONAR.

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE