Predicting Time Reversing Array Performance in Shallow Ocean Waters

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.