New Location And Geophysical Techniques For Uxo Identification In Wooded Terrains

Mapping of Unexploded Ordnance (UXO) has been significantly improved by collecting high<br>resolution, position correlated survey data utilizing differential global positioning systems<br>(DGPS). Although the use of DPGS has been effective in open areas, it is inaccurate in<br>tree/vegetative canopied areas or near structures that attenuate and reflect the DPGS satellite<br>signals. A new positioning system utilizing ultrasonic technology has been developed the<br>UlTraB (Ultrasonic Tracking) and operator guided software, which allows for high resolution<br>(centimeter accuracy), positioned correlated data in areas where GPS systems are impractical.<br>Also, a modified EM61 has been designed by Science Application International Incorporated<br>which consists of a transmitter/receiver coil with the dimensions of 0.5 meters by 1 .O meter.<br>The internal wiring of the coil has also been modified, and the unit has the capability to measure<br>three (3) different time gates (as opposed to one (1) on a standard EM61). Tests have indicated<br>that the modified unit is able to discern buried targets at shallower depths at twice the resolution<br>as compared to the standard EM61. Overall depth of exploration of the modified EM61 is equal<br>to that of the standard EM61, but resolution is increased by about two-fold.<br>This paper presents the results of a test study to demonstrate a new location system and modified<br>geophysical techniques for UXO identification in wooded terrain. A test area was created with<br>buried dummy ordnance and surveyed utilizing the Ultra@ system and the modified EM-61 in a<br>wooded terrain.