High-Speed Ray Tracing for Underwater Sound, A Status Report
Abstract
Computer simulations of underwater sound are often limited by the computer time required to trace the many paths (rays) along which sound may propagate. We have developed a high-speed ray tracing technique that is applicable to situations in which the sound speed depends on depth only, and not on horizontal position or time. Included in the model are specular reflections from a flat surface and a flat bottom, and ray bending in a vertical plane. Diffractive effects, such as propagation through caustics and leakage from ducts, are not modeled at this time. The technique is fast because the time- consuming parts of the calculations are done before the simulation starts, and the results are stored in tables. During the simulation, these results are retrieved from the tables and interpolated. The stored data consist of three functions of two variables, tabulated on a nonuniform two-dimensional grid. A doubly linked tree structure with extra links to neighboring leaves is used to permit rapid access to neighboring point in the grid. Software exists to create and fill the tables and to use the tables to plot rays and find eigenrays. Good accuracy, in most cases, can be achieved using tables of less than 100 kilobytes. Modifications are planned that will reduce the table size, improve reliability, and make the software easier to use. Our goal is to include ray tracing in simulators such as REVGEN and the NOSC Hybrid Simulator that are now limited to direct straight-line propagation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1981
- Accession Number
- ADA243518
Entities
People
- David W. Princehouse
- Robert P. Goddard
Organizations
- University of Washington