Objective

There is a need to characterize the acoustic responses of munitions and bottom clutter. The frequency range from 1-30 kHz is of particular interest for potential unexploded ordnance (UXO) detection by the Low Frequency Broad Bandwidth (LFBB) system under development by the U.S. Navy. Efforts to carry out such characterization in laboratory settings and shallow water ocean environments are under way. The present effort complements those efforts via full-scale measurements (using the same transmitting transducer as in the LFBB) in a 9-million-gallon pool facility with a sand sediment bottom. This effort represents a continuation of previous SERDP-funded experiments at the same facility carried out by the Applied Physics Laboratory, University of Washington (APL-UW) and the Naval Surface Warfare Center – Panama City Division (NSWCPCD). APL-UW’s focus is on developing and validating acoustic propagation and scattering models useful for studying the detection and classification of proud, partially buried, and buried UXO. NSWCPCD carries this effort further by integrating the resulting models into the NSWCPCD Personal Computer Shallow Water Acoustic Toolset (PCSWAT).

The objective of this project is to acquire data on proud and buried munitions over a large frequency (1-30 kHz) and aspect angle range and use these data to develop an inventory of acoustic responses of munitions and to validate propagation and scattering models that will then be implemented in finite element numerical codes and transitioned into PCSWAT. A central hypothesis is that the environment within which a UXO must be detected and classified alters the acoustic response of the target significantly and must be taken into account in order to develop robust detection/classification strategies.