Handheld Sensor for Unexploded Ordnance Discrimination
MR-200108
Objectives of the Demonstration
The objective of this project was to demonstrate that a simple, commercially available handheld sensor (Geonics EM61-HH metal detector) could be used to discriminate between buried unexploded ordnance (UXO) and clutter. The approach used for UXO/clutter discrimination with the Multi-Sensor Towed Array Detection System EM61 array in previous demonstrations was adapted for use with the EM61-HH sensor.
Technology Description
The discrimination approach uses a model-based estimation procedure to determine whether or not an unknown target is likely to be an UXO. This entails estimating the size and shape of the target from the spatial pattern of the induced field above the target. The signal is a linear function of the flux through the receiving coil. If a simple guide or template is used, the position of the EM61-HH sensor as it is swept over a target can be determined with sufficient accuracy to support discrimination. This concept depends on the reliability of the sweep pattern and the existence of a fiducial mark to register the data. The pattern is fairly repeatable, and with a fiducial mark at the center, the sensor output can be matched with position in the trajectory. Sweep motion is registered by placing a small wire loop at the center of the pattern and providing a template to guide the sweep. The EM61-HH sensor measures the induced field over two time gates.
Demonstration Results
The demonstration of the EM61-HH was conducted on the Blind Grid at the Aberdeen Test Center (ATC) Standardized UXO Technology Demonstration Site. Results of controlled test-stand measurements had indicated that 95% of detected UXO could be correctly identified as UXO, while 74% of the clutter items could be correctly classified as not UXO. In the ATC field demonstration, the corresponding performance levels were reduced to 83% and 49% respectively. The average cost per target was $31.38.
Implementation Issues
Subsequent to this demonstration, the handheld sensor was used to support a UXO cleanup action on 18 acres at a site in Bridgeport, Connecticut. The net cost for doing cued identification was $115 per target. Of the 1,546 anomalies identified in the EM61 survey, 694 items were identified as being high probability of ordnance and each item was re-acquired for cued identification using the EM61-HH. Of these items, 584 were classified as high confidence clutter, 43 as uncertain, and 67 as possible UXO.
A similar process was used at the Jeep/Demolition Range at the Former Lowry Bombing and Gunnery Range in Aurora, Colorado, to identify chemical agent shipping containers. The site covered 175 acres, and 28,014 anomalies were identified in the original geophysical survey. After the initial screening, cued identification using total field magnetometer and EM61 grids was performed for over 2,000 anomalies. Based on the results of the discrimination analysis on the cued grid data, approximately 200 targets were identified as possible chemical agent shipping containers and excavations were performed. (Project Completed - 2005)
Project Documents
Points of Contact
Principal Investigator
Dr. Thomas Bell
SAIC
Phone: 703-312-6288
Fax: 703-414-3904
Project Documents
Document Types
- Fact Sheet - Brief project summary with links to related documents and points of contact.
- Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
- Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
- Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
- Guidance - Instructional information on technical topics such as protocols and user’s guides.
- Workshop Report - Summary of workshop discussion and findings.
- Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
- Model/Software - Computer programs and applications available for download.
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