Passive broadband source localization in shallow-water multipath acoustic channels

This paper addresses the problem of direct-path passive broadband localization of a shallow-water acoustic source with a sparsely distributed set of sensors in the presence of uncertain multipath propagation. The classical approach to broadband source localization with sensors spaced many wavelengths apart involves time delay estimation (TDE) via generalized cross-correlation (GCC) methods. In shallow-water scenarios, however, multipath arrivals yield spurious peaks in cross-correlation outputs resulting in anomalous estimates of source location. In this paper, cross-correlations are normalized by an expected direct-path delay and geometrically averaged over multiple array orientations in order to disambiguate multipath returns from direct-path arrivals. In shallow-water channels, this allows for more robust estimates of the intersensor time delay due to direct-path propagation. Simulation results indicate a significant improvement in source localization performance over GCC methods operating in multipath environments.