Time delay estimation for ocean acoustic transient signal extraction in a multipath environment

Consideration is given to the problem of estimating the arrival times of overlapping or nonoverlapping ocean acoustic signals from a received signal which consists of an unknown deterministic signal along with scaled and delayed versions due to multipath propagation plus additive noise. The objective is to simultaneously determine the transmitted waveform and the arrival times. The proposed algorithm obtains approximately maximum likelihood estimates of the arrival times and the parameters which characterize the unknown signal, with much fewer computations that the direct implementation of the MLE. It is assumed that the number of the different paths is known and that the signal must belong to a parametric class of signals. The algorithm is demonstrated on a class of signals consisting of gated sinusoids