The Department of Defense (DoD) requires technology to address munitions contamination on active and former military training facilities, both marine and land-based. Marine environments, in particular, pose a significant challenge for the efficient and reliable characterization of unexploded ordnance (UXO) over wide areas. Deployment of autonomous underwater vehicles (AUV) at a wide range of sites can improve the spatial definition of UXO contamination of marine military sites. AUVs are a configurable mapping technology able to deploy an array of geophysical sensors at a wide range of marine environments for missions lasting more than 25 consecutive submerged hours, covering hundreds of acres per survey day, at minimal unit cost. The AUV-based geophysical mapping technology to be developed will exploit mature AUV technologies, related sea-mine detection capabilities, and land-based geophysical systems. Cost-effective marine-based wide area assessment methodology also will be developed.

Based on existing AUV platforms, this project will develop flexible marine surveying capabilities for wide- area screening of UXO under various marine conditions. Additionally, AUV technology will be extended for full-coverage geophysical mapping in marine environments for individual UXO detection.

A solid-body design concept for the AUV system has been established. This conceptual design houses both a 2-element EMI array and a 4-element MAG array. These models will be used to evaluate the hydrodynamic impact of the design on system performance.

This project will overcome limitations of existing marine surveying systems by integrating land-based UXO geophysical surveying technologies with mature AUV systems. Leveraging these technologies will facilitate development of AUV-based UXO mapping capabilities for underwater environments. Commercial off-the-shelfAUV systems provide deep survey capabilities, long duration operation, robust positioning systems, and simplified launch procedures. Bluefin’s AUVs used for mine countermeasures applications can be augmented to deploy magnetometers and/or electromagnetic induction (EMI) sensors for UXO detection. Proof-of-concept development of an AUV mapping system will proceed in three stages: (1) a comprehensive engineering analysis, (2) design and laboratory testing of the AUV system, and (3) testing of a functional AUV-based UXO mapping technology in a controlled environment.

This project has the potential to establish viable AUV-based marine UXO mapping with efficiency and accuracy dramatically greater than that presently available. Potential advantages compared to surface systems include low-altitude, terrain-following operations to maximize detection; AUV positioning with 1-m accuracy or better and 2-km survey range; sensor deployment independent of surface wave action; long duration missions (greater than 25 hours); increased survey productivity rates at reduced costs; integration of additional sensors (side scan sonar) with magnetometers and EMI sensors; and full grids or transects for wide area assessment.