Range Estimation by Matching the Angle Width of Multipath Echoes for a Deep-Water Active Sonar

Deep-water active sonar can be used to improve the accuracy of range estimation of a quiet target, but this technique is seldom studied. This paper focuses on the ranging problem for large-depth active sonar and studies the spatial structure of the first arrived echo group. When the target is close to the sea surface or the resolution of the direction-of-arrival (DOA) algorithm is low, we can only get two mean angles from the echo group, that is, the mean arrival angle of echoes coming from the sea surface and the mean arrival angle of echoes coming from the seabed. In this paper, an active ranging method is proposed by matching the sum of these two mean angles, which is called the angle width. Simulations based on a real sound speed profile (SSP) demonstrate the proposed method.