Phase I of the project, the Feasibility Demonstration , uses sensors towed behind a 40 foot catamaran. The catamaran provides a stable platform for the mechanical assemblies and the shack housing the target processing and data fusion computers. The sensors are carried on two pods. The back pod, the towfish, contains a sonar and a magnetic field gradiometer. The front pod, the depressor, contains two sonars and an electro-optic sensor.
The seabat is a forward-looking sonar with a range of about 100 meters. It is used to detect proud targets and for target reacquisition. Also in the depressor is the high frequency synthetic aperture sonar. It is a high resolution sensor which detects proud targets.
Suspended below the depressor is the electro-optic laser scanning sensor looking straight down. This high-resolution active sensor has over five times the range of a normal underwater camera. The depressor is attached via a 50 foot cable to the towfish which contains two sensors. The first is a low-frequency synthetic aperture sonar which penetrates the bottom and can detect shallow buried targets. Also in the towfish is the superconducting magnetic field gradiometer. The gradiometer detects variations in the earth's magnetic field due to the presence of ferrous metals. It can detect smaller ordnance, such as mortar shells, at a range of 5 meters, a fairly narrow swath beneath the sensor. Larger ordnance, such as 1000 pound bombs, can be detected, even when deeply buried, out to a distance of 50 meters. The gradiometer detects the position and magnetic moment, or size, of the nearby ferrous objects.
The data from the sensors is transmitted via cable up to the computing equipment in the shack on the catamaran. There the beamforming, target recognition, and data fusion operations are performed and feedback is supplied to the operator. The depressor is suspended from a winch assembly on the tail of the catamaran which absorbs shock from waves and wakes.
The MUDSS system is being developed in a joint effort between the Navy's Coastal Systems Station and NASA's Jet Propulsion Laboratory under the auspices of SERDP, the Strategic Environmental Research and Development Program. Phase I of the program has demonstrated the feasibility of using multiple sensors, with sophisticated data fusion techniques, to locate ordnance on the seafloor.
For some additional information on MUDSS please see the MUDSS Fact Sheets .