Many active and former military installations have ranges, training areas, and/or disposal sites that are deliberately situated in marine environments or include adjacent areas such as ponds, lakes, rivers, estuaries, and coastal ocean sites. Remediation of these sites in a cost-effective manner requires as few deployments and as few false positive targets as possible. This necessitates a highly-reliable, single-pass dynamic classification system. This project will design a marine Advanced Geophysical Classification system that combines the Gap Explosive Ordnance Detection UltraTEM sensors with the Tetra Tech TEMA platform and Black Tusk Geophysics BTField software. Design objectives are to detect and classify medium-sized ordnance with a single-pass towed platform at minimal standoff distances in water depths between 5 and 150 feet. If successfully deployed, the system will minimize two significant cost drivers in marine ordnance operations:  the number of targets to be investigated by dive teams and the duration of the data collection effort.

Technology Description

This project will utilize the multi-component multi-sensor UltraTEM time-domain electromagnetic system. The UltraTEM system can be deployed for both terrestrial and marine applications, and has proven its unique capabilities in production surveys for large-area unexploded ordnance (UXO) detection, deep bomb detection, detection of ground-engaging tools in mine stockpiles, and clearance of harbors before dredging. This project will modify the system configuration for smaller and shallower targets. The UltraTEM provides a host of unique features which allow custom configurations, including a high-current transmitter connected to multiple transmitter loops, multiple three-component receiver cubes, and a data acquisition system that is integrated with the processing modules for seamless processing and interpretation work flow.


The complete inventory of underwater Department of Defense sites with munitions and explosives of concern (MEC) contamination is currently unknown. As with terrestrial UXO detection and classification, an advanced marine sensor with strong dynamic classification ability can significantly reduce remediation costs through reduction in the number of items that need to be physically interrogated by divers. Based on the complexities and significant expense of underwater re-acquisition of targets by divers, as well as the limited budgets available for underwater MEC project sites, reduction in the number of points for interrogation and the extent of remediation of items in the marine environment is critical. This system is designed to provide single pass site mapping (eliminating the need for multiple surveys), while providing specific information about the extent of MEC contamination. The result is a significant reduction in clean-up costs and the receipt of No Further Action determinations at previously suspect sites

  • UltraTEM ,

  • System Design ,

  • Electromagnetic Induction (EMI) Sensors