The Influence of Unknown Bottom Parameters on Bearing Estimation in Shallow Water
The spatial dispersion of the sound energy in the shallow-water channel causes bearing estimates obtained by conventional beamformers or similar estimators to be biased towards broadside direction. The bias depends on such environmental parameters as the sound-speed profile and bottom parameters. Error-free bearing estimates can be obtained if the sound field is entirely known a priori. In practice, however, the bottom parameters are usually unknown. This paper discusses the problem of mismatch between the actual bottom parameters and assumptions on the processing side. Comparisons are made with an alternative method using a test source for estimating the actual channel response.
KeywordsSound Field Maximum Entropy Method Channel Response Clayey Silt Bottom Type
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