Underwater Simultaneous EMl and Magnetometer System (USEMS)

Abstract : Due to historical training and disposal activity, Munitions and Explosives of Concern (MEC) exist in the marine environment in a variety of underwater topographies ranging from open waters to bays to port areas to lakes and ponds. Although the geophysical sensors used for MEC detection in the marine environment magnetometers and pulsed EM are the same as those used in the terrestrial environment, there is not a one-size-fits-all solution due to differences in water depth. Cable-towed arrays are effective in large open areas, but may have difficulty operating in shallow or constrained areas. Project MM-0733, the Underwater Simultaneous EMI and Magnetometer System (USEMS) deploys a single total field magnetometer and commercialoff- the-shelf (COTS) EM61 submersible coil, with both sensors configured in a hydrodynamically smooth towfish. The towfish is rigidly attached behind a 17 Carolina Skiff via a six-meter boom whose angles are instrumented to provide a direct measurement of the sensors locations. USEMS was demonstrated near Plum Tree Island (Hampton) VA in September 2010.