Passive source localization in the presence of near-endfire interference

We propose an approach for suppressing near-endfire interference in shallow water environments with a passive sonar system. Reduced azimuthal resolution near endfire limits the ability of conventional beamformers to discriminate between source and interference. Our approach is to exploit the changes in the multipath wavefront, which can be sensed at a horizontal array. The idea is to use a multipath model to estimate the sequence of wavefronts which best fit the received data for a set of hypothesized range-rates. Thus a source of interest can be discriminated from interference in the same azimuthal beam on the basis of relative velocity, or range-rate.