Standard Form 298 (Rev. 8-98)Prescribed by ANSI Std. Z39.18Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information This new project is exploring the potential for developing a structural acoustics (SA) based sonar methodology for wide area search and identification of underwater unexploded ordnance (UXO). This new approach may have significant advantages over more conventional acoustic approaches, which rely on the formation of high resolution images. These advantages include: diverse set of "fingerprints" leading to low false alarm rates; longer range operation leading to wide area coverage; and low frequency sediment penetration leading to buried target prosecution. A core element of the current project is a comprehensive examination of the scattering levels and features exhibited by typical UXO targets in the SA regime using NRL's state-of-the-art underwater scattering facilities, both laboratory-based and at-sea. We have recently completed the first phase of this data collection using the laboratory-based facility, and these results are reported here.
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PROJECT BACKGROUNDMany active and former military installations have ordnance ranges and training areas with adjacent water environments in which unexploded ordnance (UXO) now exists due to wartime activities, dumping, and accidents. These contaminated areas include coastal and inland waters both in the United States and abroad. SERDP goals require the development of innovative technologies able to separate UXO from false targets and to discriminate amongst individual UXO targets themselves. Over time, such geographic areas are becoming less and less remote as the adjacent lands become further developed, and the potential hazard to the public from encounters with such UXO has begun to rise. Presently there exists no sufficiently effective capability to survey such underwater areas and map UXO locations.This new project (SERDP Project MM-1513) is exploring the potential for developing a structural acoustics (SA) based sonar methodology for wide area search and identification of underwater unexploded ordnance (UXO). This new approach may have significant advantages over more conventional acoustic approaches which rely on the formation of high resolution images.Conventional sonar approaches which form images (see Fig. 1 in Project Accomplishments Section) must operate at relatively high frequencies since the image resolution is dire...