Source localization with overlapping CW intercepts using multipath modeling

This paper addresses the problem of passively locating a CW pulse emitter without a priori information concerning the pulse duration or the number of overlapping paths being intercepted. It differs from a previous approach by Manickam [1], since it consists on jump online detections, with a single path being concerned each time. Basically, the method relies on a non-linear ML estimation of the sinusoid parameters and a jump detector based on for ward-back ward estimation residuals to compute the individual times of beginning/ending for each path. Using the sound speed profile, a non-linear (NL) least-squares fit between the measured time-delays and the guessed ones enables to locate the source in both range and depth. Monte-Carlo simulation in a deep Mediterranean like channel demonstrates the capability of the method for various signal to noise ratio. The Cramer-Rao bounds of the range-depth estimation are computed by using an analytic modelization of the ray propagation. At last, a 1-hour recorded signal experiment proves the at-sea efficiency of the method for a source located in the 20–30 km ranges of the deep Mediterranean channel.