Accession Number : ADA299146

Title :   The Effect of Ray Curvature on Lloyd's Mirror Fringe Estimates and Source Localisation.

Descriptive Note : Technical rept.,

Corporate Author : DEFENCE SCIENCE AND TECHNOLOGY ORGANIZATION CANBERRA (AUSTRALIA)

Personal Author(s) : Lewis, P. R.

PDF Url : ADA299146

Report Date : SEP 1994

Pagination or Media Count : 31

Abstract : A knowledge of the interference between direct, surface and bottom reflected rays emanating from a moving underwater source can be used to determine the source detector relative positions. Using simple ray tracing, the frequency time interference patterns for a broadband frequency source arising when the propagating medium has a piecewise linear sound speed profile are considered, and are compared with those for a constant sound speed. It is found that even small deviations from a constant sound speed can lead to a noticeably different interference fringe placement and shape, and consequently to the inferred source detector geometry. Further, comparisons of model calculations to experimentally observed fringe systems demonstrate the inadequacy of the constant sound speed model, whereas tbe use of tbe simple segmented profile is capable of replicating the observed patterns.

Descriptors :   *SONAR SOUND ANALYZERS, MIRRORS, PROPAGATION, COMPUTATIONS, DETECTORS, MOTION, REFLECTION, ESTIMATES, CURVATURE, PROFILES, MODEL TESTS, BROADBAND, INTERFERENCE, PATTERNS, GEOMETRY, AUSTRALIA, RAY TRACING, ACOUSTIC VELOCITY, BOTTOM, SEGMENTED, UNDERWATER.

Subject Categories : Acoustic Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE