Accession Number:

ADA626425

Title:

Predicting Time Reversing Array Performance in Shallow Ocean Waters

Descriptive Note:

Corporate Author:

MICHIGAN UNIV ANN ARBOR DEPT OF MECHANICAL ENGINEERING

Personal Author(s):

Report Date:

2001-09-30

Pagination or Media Count:

6.0

Abstract:

Long-Term Goals The long term goals of this project are i to predict and understand the characteristics of active and passive time reversing array TRA performance in shallow water ocean waters, and ii to deduce the effectiveness of using a TRA for underwater communication and for surveillance of the acoustic characteristics of known or unknown environments. Objectives This project seeks to quantitatively predict TRA performance in shallow ocean environments. Here performance includes retrofocus field amplitude, location, size, and longevity and the correlation of the retrofocused signal with the original signal. The intent is to predict these quantities as a function of signal frequency and bandwidth, source-array range, array orientation, noise level, source motion, array motion, and array configuration in shallow ocean sound channels containing realistic propagation complexities. Such complexities include dynamic random shallow-water internal-waves, noise, bottom losses, and three-dimensional acoustic scattering. The challenge here is to ascertain generic features and scaling laws in the presence of wide natural variability. Such results form the starting point for the design of practical TRA systems. While past work on this project has concentrated on narrowband signals in dynamic 1,2 and noisy 3 environments having weak azimuthal scattering 4, the current effort emphasizes array orientation 5, broadband signals 6,7, the effects of source and array motion, and three-dimensional environments.

Subject Categories:

  • Physical and Dynamic Oceanography

Distribution Statement:

APPROVED FOR PUBLIC RELEASE