ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

2aUW27. Shallow water source track localization using matched multipath correlations.

D. P. Knobles

Evan K. Westwood

K. C. Focke

Appl. Res. Labs., The Univ. of Texas at Austin, Austin, TX 78713

A method for localizing a broadband moving source using the signals received on a horizontal planar array is presented. The method involves finding the constant-velocity, straight-line source track that generates the least error between measured and modeled correlation traces over a period of time. Measured correlation traces are obtained by cross-correlating multiple pairs of received time series. Simulated correlation time delays are obtained using a ray model that includes the effects of refraction on the ray arrival times. A nonlinear optimization routine is used to obtain the best match in measured and simulated time delays over time and receiver pair. The main problem in shallow water is to identify which multipath pairs produce the correlation traces observed in the measured data. An approach for overcoming this problem that involves testing multiple hypotheses concerning the multipath pairs will be presented. An example application of the method to a shallow water dataset with three bottom-mounted receivers in a triangular configuration is presented. In order to validate the localization, the measured correlagram is compared with a correlagram produced by a broadband normal mode model using the derived source track. [Work supported by the Office of Naval Research (Code 322).]