Accession Number : ADA198001

Title :   Effects of Water-Depth Mismatch on Matched-Field Localization in Shallow Water,

Corporate Author : NAVAL OCEAN RESEARCH AND DEVELOPMENT ACTIVITY NSTL STATION MS

Personal Author(s) : Del Balzo, Donald R. ; Feuillade, Christopher ; Rowe, Mary M.

Report Date : JUN 1988

Pagination or Media Count : 6

Abstract : This article discusses the impact of incorrect estimates of the water column depth on matched-fielded source localization in shallow water. Computer calculations were performed for the case of a nominal 100-m depth water column subject to water-depth variations of up to + or - 3.5m, which would be caused by long-period ocean swell or by tidal changes. The calculations incorporated source depths of 25, 50, and 75 m, a propagation distance of 4 km, an acoustic frequency of 150 Hz, and a linear vertical receiving array. The array consisted of 21 hydrophones with an interelement spacing of 2.5m, and it spanned the center one-half of the water column (25- to 75-m depth). The matched-field algorithm used in this study is high-resolution maximum-likelihood estimator. A primary result of the work is that, as the output of the matched-field processor degrades due to water-depth mismatch, the apparent source location varies in a systematic way, i.e., the source appears closer and deeper for increasing water depth and, conversely, the source appears farther and shallower for decreasing water depths. Reprints. (edc)

Descriptors :   *SHALLOW WATER, AUDIO FREQUENCY, COMPUTATIONS, COMPUTER APPLICATIONS, DEPTH, LONG RANGE(TIME), OCEAN WAVES, PROPAGATION, RANGE(DISTANCE), REPRINTS, SOURCES, OCEAN TIDES, SEA WATER, ESTIMATES, ALGORITHMS, MATCHING, HYDROPHONES, ACOUSTIC ARRAYS, MAXIMUM LIKELIHOOD ESTIMATION, SOUND TRANSMISSION.

Subject Categories : Physical and Dynamic Oceanography
      Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE