Remote Sensing in Fluctuating Range-Dependent Littoral Environments with Clutter

Abstract

To understand and characterize acoustic clutter and background reverberation in long range sonars operating in range-dependent continental shelf environments. Develop operational and signal processing techniques to distinguish biological or geological clutter from scattered returns due to manman targets. In the second area, the dominant causes of fluctuation in measured acoustic signals is examined and used to determine the extent to which environmental variabilities limit our ability to perform source localization and environmental parameter estimation through match-field processing and beamforming in fluctuating ocean waveguides. APPROACH The approach combines analysis of experimental data acquired using a long range sonar system with development of theoretical physics-based multi-static scattering and reverberation models. The acoustic data analysed in this proposal are from the Geoclutter 2001 and 2003 experiments on the New Jersey Strataform.[1,2] In Sep. 2006, we acquired another brand new set of acoustic data with a long range sonar on Georges Bank in the Gulf of Maine. Our approach involves the following. Identify and determine the dominant sources of scattering and reverberation in continental shelf environments Correlate scattered field levels with physical and acoustic properties of the scatterer. Develop models for target scattering and environmental reverberation in fluctuating, dispersive, and range-dependent continental shelf environments Develop inverse methods for estimating properties of objects from their scattered fields. Develop signal and image processing methods to distinguish man-made targets from biology and other features in the environment. WORK COMPLETED AND RESULTS 1. Design and Conduct of OAWRS Experiment 2006 on Georges Bank We designed and conducted a major ocean acoustics waveguide remote sensing (OAWRS) experiment off the Gulf of Maine from Sep 18 to Oct 7, 2006. The experiment involved coordinating resources, personnel and equipment on board 4 research vessels. A low frequency long range active sonar was 18. NUMBER OF PAGES 7 19a. NAME OF RESPONSIBLE PERSON