Novel Acoustic Technique for UXO Discrimination

Abstract : Recent demonstrations have shown that magnetic and electromagnetic induction technology can reliably detect most buried unexploded ordnance (UXO). Unfortunately, current technology is unable to reliably discriminate between UXO and other items that pose no risk, and typical survey methods currently deployed have an excessive level of false alarms (i.e. marking of sub-surface anomalies that do not correspond to UXO). There is a need for systems that, when cued by standard survey technologies, can cost effectively, non-invasively interrogate the suspected item and discriminate. One distinguishing characteristic of UXO is its shape: projectiles, mortars, bombs and rockets are characteristically long and slender. Over the past few years, several Strategic Environmental Research and Development Program (SERDP) and Environmental Security Technology Certification Program (ESTCP) sponsored projects have shown varying degrees of success in developing techniques for using magnetics and electromagnetic induction to discriminate between different target shapes [1]. This report documents the results of a SERDP Exploratory Development (SEED) project that applies a complementary sensor technology to the problem. The objective of the project was to demonstrate that relatively simple seismic technology routinely used for pavement and soil mechanical analysis can be used for classification and discrimination of buried objects. This report has six sections. Following this introduction, section 2 gives the background for the project, and the basic concept is described in section 3. Details of the experimental work done for this project are documented in section 4, and our conclusions are presented in section 5. Section 6 lists references cited in the report. Because of shortcomings of the instrumentation used in this project, the results are not conclusive. We measured signals that are qualitatively similar to those expected on the basis of numerical studies, but the spatial and freque