ADAPTIVE BEAMFORMING WITH NEAR INSTANTANEOUS CONVERGENCE IN A PASSIVE AND ACTIVE SONAR SYSTEMS

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Authors
  1. Dhanantwari, A.C.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);Technical Univ of Nova Scotia, Halifax NS (CAN) Dept of Electrical Engineering
Abstract
In RADAR and SONAR applications, the detection of weak signals with conventional beamformers is not always possible because of the anisotropic nature of the noise fields and the presence of strong interferers. Adaptive beamformers can provide increased array gains, improved angular resolution, and interferer cancellation, which lead to better detection of weak signals. However, these beamformers have major practical disadvantages which are due to their extremely long convergence periods and excessive computational requirements. For matched filter processing the adaptive beamformers are required to produce continuous beam time series that have sufficient temporal coherence to correlate with the reference signal, and should achieve near-instantaneous convergence. This effort investigates the concept of partially adaptive beamforming by implementing the adaptive beamformers in the sub-aperture configuration as a solution to the problem. The memoryless Generalized Sidelobe Canceller (GSC) and Steered Minimum Variance (STMV) beamformers in the sub-aperture configuration with synthetic and real data shows that they achieve near-instantaneous convergence. Also, the correlator outputs show that the beam time series generated by the adaptive beamformers have temporal coherence equivalent to those of the conventional beamformer and correlate with the reference FM signal.
Keywords
Adaptive signal processing;Anisotropic noise;Sub-aperture configuration;Convergence
Report Number
DREA-CR-97-429 — Contractor Report
Date of publication
01 Jul 1997
Number of Pages
131
DSTKIM No
97-03925
CANDIS No
504198
Format(s):
Hardcopy;Document Image stored on Optical Disk

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