Time-Reversing Array Focusing in Shallow Ocean Waters

摘要

The long-term goals of this project are as follows: (1) to predict and understand time reversing array (TRA) retrofocus size and longevity in a shallow water acoustic environment based on acoustic, geometrical, and environmental parameters; and (2) to deduce the effectiveness of using a TRA for monitoring and/or determining the acoustic properties of unknown environments. The specific goals of this project are to determine TRA retrofocus size and longevity in the presence of a linear superposition of dynamic random shallow water internal waves, noise, and three dimensional effects typical of the shallow ocean. In particular, the influence of acoustic frequency, source array range, and propagation in a dynamic mulitpath sound- channel on time-reversing array retrofocusing is not completely understood. The challenge here is to separate the various influences and impacts of propagation complexities (bottom losses, water-column dynamics, noise, three-dimensional scattering, etc.) so that the phenomena primarily responsible for TRA retrofocusing persistence and limitations can be identified. While our past work dealt with simple dynamic environments, the current effort incorporates realistic oceanic sound propagation to a much greater degree.