A matched-field processing approach to ranging surface vessels using a single hydrophone and measured replica fields.

A matched-field processing (MFP) approach is proposed to provide instantaneous estimates of the horizontal range of a surface vessel moving in shallow water, using a single hydrophone located above the sea bottom. The field to be matched is the cepstrum of the acoustic signal received at the hydrophone. A set of replica fields (cepstra), each at a known horizontal range, is generated using the recorded acoustic data for a typical surface vessel transit in the area of interest. The instantaneous horizontal range of any surface vessel moving in the same area of interest is estimated by finding the replica field that best matches the observed field. The proposed method is tested using real acoustic data recorded from a bottom-mounted linear array of eight hydrophones, for six transits of a small ship and a single transit of a rigid-hulled inflatable boat in shallow water. In this experiment, the replica fields are generated using the acoustic data from the two hydrophones at both ends of the array for one of the small ship transits. The proposed MFP method is applied, in turn, to the acoustic data from each hydrophone for each vessel transit, and the results demonstrate the effectiveness of the method.