Time-Reversing Array Focusing in Shallow Ocean Waters

Abstract

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.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1998
Accession Number
ADA551664

Entities

People

  • David R. Dowling

Organizations

  • University of Michigan

Tags

Communities of Interest

  • Human Systems

DTIC Thesaurus Topics

  • Acoustic Frequencies
  • Acoustic Properties
  • Acoustic Scattering
  • Applied Mechanics
  • Bottom Loss
  • Dynamics
  • Energy Levels
  • Engineering
  • Environment
  • Frequency
  • Internal Waves
  • Measurement
  • Mechanical Engineering
  • Mechanics
  • Scattering
  • Shallow Water
  • Three Dimensional

Readers

  • Acoustical Oceanography.
  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.