Objective

The potential UXO contamination of nearly 10 million acres of marine and lacustrine environment has facilitated the need for detection technologies suited for underwater deployment. While ground-based sensing methodologies have generated some success when applied to the underwater environment, the fundamental electromagnetic characteristics of marine media will require an alteration of terrestrial paradigm to fully exploit these conventional methodologies. Specifically, there is much evidence that employing electromagnetic modes that are higher in frequency than those typically used in ground based sensing will yield greater range and sensitivity for underwater surveys. We propose to complete an extensive study of the application of relevant electric and magnetic sensing techniques to the complex underwater environment. By fully characterizing these electromagnetic phenomena in the marine environment, we will reveal sensing modalities that will optimize detection of underwater UXO.

The principal objective of this research is to evaluate the information content in the very low frequency/low frequency (VLF/LF) (10 kHz to 1 MHz) range to exploit both magnetic and electric field information for detection, localization, and discrimination of underwater UXO. We will develop potential design strategies for implementing both magnetic and electric field sensors in the marine environment, and we will determine the best arrangement for a potential combined electric and magnetic field sensing system with the goal of sensing fields at 1-4 m standoff over the frequency range 100 Hz to 1 MHz. Fabrication, testing, and evaluation of a prototype underwater electric and magnetic field sensing system will culminate this effort.