Use of trapped and propagating mode energy ratio for discriminating between the surface target and the underwater target

Abstract

The surface target and underwater target discrimination is an urgent and difficult problem in the field of underwater acoustical research. Using the dominant mode difference of the surface source and underwater source acoustic fields in shallow water with the thermocline, the beamforming spatial filters are designed to estimate the refracted mode energy and the propagating mode energy. Further, the energy ratio is used to discriminate between the surface and underwater target. The simulation results show that when the horizontal receiving array is in or under the thermocline, the target not abeam can be accurately discriminated using the method. Moreover, the wider the processing frequency band is, the larger the array aperture is, the greater the difference between the critical and target depth is, and the higher the discrimination accuracy.