Wide Area Detection and Identification of Underwater UXO Using Structural Acoustic Senors: 4th Annual Report to SERDP MM-1513

Abstract : This project is exploring the development of a structural acoustics (SA) based sonar methodology for wide area search and identification of underwater unexploded ordnance (UXO). This approach has significant advantages over conventional acoustic approaches relying on formation of high resolution images including: diverse set of "fingerprints" leading to low false alarm rates; longer range leading to wide area coverage; and low frequency sediment penetration leading to buried target prosecution. A core element of the project is an examination of the scattering 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 extended the original mono-static data base to include bi-static data from proud and partially buried targets, examined the special case of forward scattering and how it might be exploited, connected laboratory UXO scattering measurements to those made in St. Andrew's Bay by employing an advanced acoustic multi-path propagation model, and examined the scattering from proud and buried targets on smooth and rough sediment surfaces using an elasto-dynamic finite integration technique (EFIT) numerical simulation model.