Accession Number : ADA579916


Title :   Low-Cost Ultra-Wideband EM Sensor for UXO Detection and Classification


Descriptive Note : Final rept. Apr 2011-Apr 2012


Corporate Author : EARTH SCIENCE SYSTEMS LLC WHEAT RIDGE CO


Personal Author(s) : Oden, Charles P


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA579916


Report Date : Apr 2012


Pagination or Media Count : 31


Abstract : This SERDP SEED project investigated the viability of using low-cost commercially available magneto-resistive sensors for EM induction and magnetometry. Because there are many different configurations for operating these sensors, a custom circuit board was designed and fabricated to determine which configuration would be most optimal for UXO detection and discrimination. Noise and sensitivity measurements were conducted in the frequency domain using a Helmholz coil. Magnetic biasing , electrical bridge biasing, chopper techniques, and open/closed loop configurations were investigated. The optimal configuration produced a noise density of 6 pT/vHz for frequencies above 200Hz. At 1 Hz, the noise density is - 30 pT/vHz. These results were obtained in both open loop and closed loop operation. A laboratory prototype instrument was built using the magneto-resistive sensors to test the magnetometer and EM induction response to actual UXO targets and compare with readings from similar instruments. When operating in magnetometer mode, the prototype detected an 81 mm target at a distance of over two meters. When operating in time-domain EM induction mode, measurements could be made as early as 20 us after the transmitter turn-off.


Descriptors :   *UNEXPLODED AMMUNITION , ELECTROMAGNETIC INDUCTION , MAGNETOMETERS , MAGNETORESISTANCE , ORDNANCE LOCATORS


Subject Categories : Ammunition and Explosives


Distribution Statement : APPROVED FOR PUBLIC RELEASE