Purpose:

The Department of Defense has millions of acres of land and over 1,000 sites at which buried unexploded ordnance (UXO) is a potential hazard to human beings and to the environment. Existing technologies for addressing this problem have proven insufficient, and technical advances are urgently needed to increase the efficiency of characterizing and remediating these lands. Magnetometers and electromagnetic induction devices have demonstrated substantial capabilities for detecting metallic subsurface objects. However, the U.S. Army Corps of Engineers estimates that about 70 percent of remediation costs are typically consumed by digging at "false-alarm" locations. That is, the detection systems find something in the locatioms, but what they discover are substances other than buried ordnance. The purpose of this project is to employ a new, broadband, fully polarimetric radar system to aid in discriminating subsurface ordnance from non-ordnance items.

Description:

The system being demonstrated employs a combination of traditional UXO detection methods and the new broadband radar technology. Once "hot spots" have been identified at a site by the lower frequency systems, more complete information is obtained at the higher radar frequency band being demonstrated. The new radar system, developed by the Ohio State University Electroscience Laboratory, consists of an orthogonal set of hornfed dipole antennas, controlled by a network analyzer over the ultra-wideband 20 MHz to 420 MHz. The nature of the feed permits a reliable input without distortion by ground loading. Rotation of the opposing dipole configuration produces complete polarization information, with sensitivity to target orientation, while providing orientation-independent characterization as well. Recording of the cross-polarized reflections avoids signal saturation by reflections from the ground surface or from other interfaces that are not of interest. In addition to providing orientation data, the radar's ultra-wideband spectrum facilitates inference of target depth and length. New special purpose algorithms will also be tested to infer target aspect ratio, gross shape, and some morphological detail (e.g. fins).

Benefits:

At the most general level, this project will help evaluate whether radar can be useful for UXO discrimination, and which site conditions favor or discourage its use. The particular value of this project's test system lies in its potential for discriminating subsurface target characteristics; helping distinguish UXO from non-ordnance items. A consequent reduction in false-alarm rates would result in very substantial savings in time and money at UXO remediation sites. (Anticipated Project Completion - 2005)

Contact:

Dr. Kevin O'Neill
U.S. Army Corps of Engineers
Cold Regions Research & Engineering Laboratory
72 Lyme Road
Hanover, NH 03755
Telephone: (603) 646-4312
Fax: (603) 646-4640
E-mail: Kevin.O'Neill@erdc.usace.army.mil