Research On Underwater Sound Channel Simulation And Sound Ray Revision

For the sound rays propagate along the spacial curves in the submarine inhomogeneous medium, sound velocity displays difference on each point of the sound ray. With a typical weak negative gradient velocity distribution, the ray bending takes neglected influence on the long baseline acoustic positioning system, whose single hydrophone range coverage 6 kilometer. This dissertation is committed to amend ray bending of long baseline acoustic positioning system.The dissertation's research mainly includes the submarine sound field simulation, the sound ray revision algorithm and the algorithm's project realizing and validating.Firstly, a mathematical model of multi-path channel is established using the theory of sound ray to simplify the underwater sound channel assumption of stratified ocean medium and smooth interface. The coarse searching algorithm and subtle Newton's iterative searching algorithm of eigenrays represented by the combination of several specified ray spans are combined to search all the important eigenrays quickly and correctly, thus the sea sound field is simulated. The comparison between experimental field data and simulated data confirms this model primarily.Secondly, the basic varying rule of effective sound velocity in marine has been obtained by the simulations based on the model of multi-path channel. The concept of effective sound velocity is used to calculate quantitatively the positioning deviation caused by sound ray bending.Thirdly, the table building method and the local region linearity interpolation table checking method based on distance or time delay are advanced. The direct table checking algorithm and the clock deviation optimizing algorithm are proposed for sound ray revision in a synchronization positioning system and a non-synchronization one respectively.Finally, an expert system module utilizing multi-path channel model and a sound ray revision module utilizing effective sound velocity are designed for underwater target tracking system.The results of simulated data and experimental field data processing validate the multi-path channel model and the sound ray revision method.