ANALYSIS OF ARCTIC ACOUSTIC DATA (II); MODELLING AND PREDICTION OF ARCTIC AMBIENT NOISE CHARACTERISTICS

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Authors
  1. Greening, M.V.
Corporate Authors
Defence Research Establishment Pacific, Victoria BC (CAN);Datavision Computing Services Ltd, Victoria BC (CAN)
Abstract
The following report details the work completed on using focalization to estimate source locations when the bottom bathymetry is not exactly known. This technique allows modelling of multiple broad-band sources and permits bounds on the bottom bathymetry. It was found that both single and multiple sources could be found when all sources are sought simultaneously but are not always found when sources are sought one at a time. It was also found that sources occuring over steep slopes were the easiest to localize while sources occuring over flat bottom sections were harder to localize because of the larger sidelobes in the ambiquity surfaces resulting from these sources. The best matching technique for localizing events was found to be summing coherently over both frequency and hydrophones without using the autospectum. However, all techniques which summed coherently over hydrophones was found to produce similar results. When examining real data, the estimated source locations were consistant when using different random starting locations and between different data files thought to contain the smae events. This suggests that the estimated source locations may correspond to true events. However, the large mismatch (0.092-0.12) found with real data allows for the possibility that the estimated source locations may not be correct.
Report Number
DREP-CR-94-110 — Contractor Report
Date of publication
01 Mar 1994
Number of Pages
52
DSTKIM No
94-03648
CANDIS No
143606
Format(s):
Document Image stored on Optical Disk;Originator's fiche received by DSIS

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