Abstract:

To address the dependency of high-precision underwater positioning models on ray-tracing algorithms, this paper proposes a static acoustic delay compensation positioning model. Inspired by the GNSS atmospheric static delay model, a conventional sound speed (defined as the speed of sound in seawater) is established. A mapping function model between the zenith acoustic delay and the slant-range acoustic delay, dependent on the elevation angle, is constructed alongside its nonlinear least-squares parameter estimation algorithm. This approach transforms the sound speed profile into static acoustic delay and mapping function information products, enabling static acoustic delay compensation directly on the slant-range observations in the acoustic ranging positioning model. The proposed second-order continued fraction based on the sine of the elevation angle can accurately approximate the acoustic delay mapping function. When combined with dynamic acoustic delay compensation, it not only achieves centimeter-level precision for seafloor geodetic positioning but also improves computational efficiency by approximately 80% compared to traditional methods and by over 50% compared to existing fast ray-tracing algorithms. The static acoustic delay compensation positioning model proposed in this study provides a valuable reference for theoretical research in underwater acoustic ranging and positioning and offers a novel solution for constructing large-scale underwater acoustic navigation and positioning service information products.

Key words: underwater acoustic positioning, fast ray-tracing, mapping function, zenith delay