Effective Calculation Methods of Reference Sound Velocity in Shallow Sea Environment

Abstract

The conventional underwater passive direction finding method estimates the target angle through beamforming. The reference sound velocity in horizontal linear array beamforming should use the phase velocity of sound propagation. In passive direction finding, because the target distance is unknown, there is a deviation between the reference sound velocity selected in the target angle estimation and the phase velocity, which affects the direction finding accuracy. In this paper, two methods for calculating the reference speed of sound are presented: the normal amplitude weighting method and the beamforming method. The numerical simulation results under shallow sea propagation condition show that the reference sound velocity calculated by the two methods has the same trend as the distance between target and array.