Electromagnetic Induction and Magnetic Sensor Fusion for Enhanced UXO Target Classification

摘要

Traditional methods for buried unexploded ordnance (UXO) detection, characterization, and remediation are labor-intensive, slow, and inefficient. A large portion, approaching 70% in some cases, of the total budget of a typical remediation effort is spent on digging targets that do not turn out to be UXO. The Environmental Security Technology Certification Program (ESTCP), has supported the Naval Research Laboratory (NRL) in developing the Multi-Sensor Towed Array Detection System (MTADS), to address these deficiencies. It is efficient and simple to operate by relatively untrained personnel. It can detect and locate ordnance with accuracies on the order of 15 cm. However, even with careful mission planning and site-specific training, there are still significant numbers of nonordnance targets selected. Most UXO fit a specific profile: they are long and slender with typical length-to-diameter aspect ratios of four or five. Many clutter items, on the other hand, do not fit this profile. Using electromagnetic (EM) pulsed-induction sensor data, we have developed a model-based estimation procedure that relies on exploiting the dependence of the induced field on target size, shape, and orientation to determine if a target is likely to be a UXO item. These methods were the subject of two demonstrations. The first demonstration was conducted in August 1999 at a live test range, the L Range at the Army Research Laboratory s (ARL) Blossom Point Facility. Towed-array magnetometer (one pass) and EM pulsed- induction data (two orthogonal passes) over the 3 acre site were collected in 12 survey hours. After analysis of the resulting data sets, 201 targets were classified by their EM response coefficients and flagged for remediation. Target remediation and identification required 12 man-days. Of the 188 targets recovered from this test area, 66 were ordnance items, 20 were ordnance-related items, 66 were exploded fragments, and 36 were items not related to ordnance.