Contact depth localization - sensitivity to environmental variability

A contact depth recognition technique has been developed which uses the multipath structure of a point target echo and hence the channel structure as a discriminator. The technique uses a template matching approach of predicted multipath structure. Multipath structure is predicted using the Comprehensive Acoustic Sonar Simulator (CASS) model. Inputs to the model, such as sound speed profile, bottom bathymetry and boundary reflection coefficients are modeled using the variability observed in real world environments. This paper addresses the sensitivity of contact depth localization to environmental uncertainty. A method to parameterize environmental uncertainty has been developed and it is used to derive the statistical characterization of the performance of the depth estimation algorithm. Robust depth localization performance is demonstrated for oceanographic variability scales consistent with real world operating environments.