Bearings-Only Target Motion Analysis using Ray Tracing

Abstract

Target angular information in a 3-dimensional space consists of an elevation angle and an azimuth angle. The azimuth angle indicates the direction of the target in a horizontal plane while the elevation angle indicates the direction of target signal in a vertical plane established from a passive line array sonar. The acoustic signals gathered by the line array sonar have different elevation angles as they propagate through multiple paths. The target angle measured by the line array sonar is, in fact, a conical angle that indicates the direction of incoming signal to the line array sonar system. Therefore, bottom bounce path produces an inaccurate target location if it is interpreted as the azimuth angle in the horizontal plane as is commonly used in exiting Target Motion Analysis (TMA) technologies. Therefore, it is necessary to consider the conical angle effect on bearings-only TMA (BO-TMA). In this paper, the conical angle of target that causes angular ambiguity will be simulated, and the BO-TMA method using Particle Swarm Optimization (PSO) is proposed to solve the angular ambiguity problem. © 2019 IEEE.