Alternative Models for Calculation of Elevation Angles and Ray Transit Times for Ray Tracing of Hydrophonic Tracking Data

摘要

This thesis treats the problem of determining the elevation angle needed to initialize an underwater sound ray tracing algorithm used to locate the position of a target vehicle. At regularly spaced time intervals the vehicle pings a synchronized sound signal which is received by a (short base line) sonar array containing four hydrophones positioned at four of the corners of a cube. The wavefront direction angles are determined from the arrival times at the four hydrophones. Current methods for using such time data to produce an apparent position suitable for ray tracing are reviewed. Then four new methods are developed and documented mathematically. All methods are compared under a simulated environment of a sound speed profile which is linear with depth. One of the new methods is judged to be an improvement over current methods in this idealized environment. Finally the improved method is used to estimate the variability in the time data from a real hydrophonic tracking problem.