A simplified method of sound speed profiles for precise positioning of underwater dynamic targets

The accuracy of underwater acoustic positioning is seriously affected by the spatiotemporal variations of sound speed. For precise positioning of seafloor fixed points, the simplified reference sound speed profiles (SSPs) are commonly adopted to correct the influence of these variations. However, in underwater dynamic target positioning, the simplified method that only considers acoustic ray tracing equivalence at fixed depths can lead to significant representativeness errors at other depths. To address this issue, we propose a criterion for minimizing acoustic ray tracing errors through the entire depth range and then employ a metaheuristic algorithm to solve the combinatorial optimization problem involved in this criterion. The results show that, compared to the maximum sound speed deviation, area difference, and genetic algorithm based on the minimum acoustic ray tracing error criterion at fixed depth methods, the SSP simplified by the proposed method exhibits higher geometric accuracy, acoustic ray tracing accuracy, and positioning accuracy through the entire depth range. The proposed method is suitable for underwater dynamic target positioning, especially in scenarios with significant depth variations.