INTENSITY MEASUREMENTS AND OPTIMUM BEAMFORMING USING A CROSSED DIPOLES ARRAY

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Authors
  1. Franklin, J.B.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
The measurement of ambient noise directionality, the determination of the acoustic intensity produced by an acoustic source and the detection of targets is of considerable interest to the underwater acoustics community. Pressure and pressure gradient signals can be combined multiplicatively (intensity probe) or via optimum beamforming to provide directional information. Estimates of signal intensity and target detection can be achieved using both methods. The measurements made using either processing method are degraded by noise, statistical fluctuations, and errors in channel gain and phase. Both processing methods are described and the degradation in performance introduced by channel errors and self-noise is derived. The standard deviation on the estimates of intensity by the optimum beamformer is smaller than that obtained by the intensity probe. However, the optimum beamformer is more sensitive to channel errors than the intensity probe. The lower standard deviation observed for the optimum beamformer translates into a significant improvement in target detection performance over that obtained using intensity probe processing.
Keywords
Acoustic intensity;Crossed dipoles array;Target detection
Report Number
DREA-CR-97-443 — Contractor Report
Date of publication
01 Oct 1997
Number of Pages
22
DSTKIM No
98-00596
CANDIS No
507347
Format(s):
Hardcopy;Document Image stored on Optical Disk

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