Processing techniques applied to underwater target echoes and their relationships

• Published in: The Journal of the Acoustical Society of America 2009-04, Vol.125 (4_Supplement), p.2608-2608
• Main Authors: Houston, Brian H., Bucaro, Joseph A., Kraus, Larry, Simpson, Harry J., Yoder, Timothy J.
• Format: Article
• Language: English
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4783932

Interest in acoustic scattering from underwater unexploded ordnance (UXO) has been increasing because of the growing need for sonar technology able to detect submerged UXO and to efficiently separate these detections from those due to natural and man-made clutter. Recent efforts range from laboratory and numerical studies seeking to understand the basic structural acoustic echo formation processes and the environmental effects on them to field exercises determining how well a particular detection/identification technology performs. This paper discusses several important scattering-based constructs, which have been utilized in both the basic UXO studies and the technology exercises as well. They include: (1) σ(ω, θ), the frequency/angle-dependent scattering cross section; (2) standard imagery, oftentimes implemented with synthetic aperture arrays; (3) reflection tomography imaging; and (4) supersonic imaging using holographic techniques. Without a clear appreciation for the differences among the constructs, it is difficult to properly relate the results of the various studies. We have measured the broadband scattering from several underwater UXO targets using laboratory, rail-based, and AUV systems and processed the data using the above constructs. The use of a common, high quality UXO scattering data base in this process helps clarify the differences and relationships among the constructs. [Work supported by SERDP and ONR.]