SUPERDIRECTIVE RECEIVING ARRAYS FOR UNDERWATER ACOUSTIC APPLICATION

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Authors
  1. Franklin, J.B.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
Superdirective arrays provide directivity with less aperture than that required by conventional arrays yielding the same directivity index. Both circular and line configurations for the superdirective array are addressed in this report. The line array is based on the computation and combination of pressure gradients extending to high order whereas the circular array involves the computation and combination of spatial harmonics. The gradients or harmonics can be weighted and combined to optimize the array gain of the array. This is done for three noise fields: 3-D Isotropic noise, 2-D Isotropic noise and sea surface noise. It is shown that the high frequency limit for a given array is set by the dimensions of the array and that the low frequency limit is set by the degradation introduced by position error, self-noise which is wavenumber white and channel imbalance in gain and phase. An application of superdirective arrays as receivers for a parametric sonar is described.
Keywords
Line arrays;Circular arrays;Array gain;Parametric arrays
Report Number
DREA-CR-97-444 — Contractor Report
Date of publication
01 Oct 1997
Number of Pages
45
DSTKIM No
98-00595
CANDIS No
507348
Format(s):
Hardcopy;Document Image stored on Optical Disk

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