Range-dependent matched field source localization and tracking in shallow water on a continental slope region of the North-East Pacific Ocean.
Date
1998
Authors
Taillefer, Martin Luc
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Abstract
Source tracking using a vertical line array (VLA) is not possible in general unless the cylindrical symmetry of the acoustic field is broken. This thesis describes the analysis of matched-field (MF) source localization data from an experiment over the continental slope off Vancouver Island. A CW source was towed along a radial track over the slope out to ranges of 5.5 km, and then along a navigational arc in water depths from 380 m at the array to 750 m. The data were collected using a multi-element vertical line array (MEVA). The MEVA is a 16-element array with sensors evenly spaced at depths between 90 m and 315 m. The environment was modelled using an adiabatic normal mode approximation that accounted for elastic wave propagation in the sediment layers. A bathymetric database of the experimental region was compiled to provide a reliable set of depth contours used for computing the acoustic replica-fields. Using a Bartlett MF processor, the source was tracked in range, depth and bearing over the duration of the track, with Bartlett processor values of up to 0.88. The analysis and results presented here demonstrate remarkably good tracking performance indicating that the slope is effective in breaking the symmetry of the acoustic field to provide bearing resolution with a VLA.