Standardized UXO Technology Demonstration Site Scoring Record No. 920 (NRL). MTADS Discrimination/Towed
Abstract
This scoring record documents the efforts of NRL, to detect and discriminate inert unexploded ordnance (UXO) utilizing the YPG Standardized UXO Technology Demonstration Site blind grid. The MTADS Discrimination array consists of 25 individual EMI sensors arranged in a 5 x 5 array. The center-to-center distance is 40 cm yielding a 2 m x 2 m array is the position of the three GPS antennae that are used to determine the location and orientation of the array for each cued measurement. Each individual sensor includes a 35-cm transmit coil and an inner, 25-cm receive coil. Decay data are collected with a 500 kHz sample rate until 25 ms after turn off of the excitation pulse. These raw decay measurements are grouped into 115 logarithmically-spaced "gates" whose center times range from 42 microseconds to 24.35 milliseconds with 5% widths. Application of this technology is straightforward. A list of target positions is developed from a survey by some geophysical instrument; in the case of this demonstration, the earlier survey by the MTADS magnetometer array. This target file, containing the target location and some estimate of target depth, is transferred to the system control program which uses the information from the three GPS antennae to guide the operator to position the array over each target in turn. When positioned over the target, we step through the array sensors sequentially, just as in the characterization measurements discussed in the preceding section, and collect decay from all twenty-five receive coils for each excitation. These data are then inverted for target location and characteristics. At the end of the EMI data collection, a few seconds of platform position and orientation data are collected to be used to translate the inverted target position, which is, of course, relative to the array, to absolute position and orientation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 2008
- Accession Number
- ADA494180
Entities
People
- Christina Mcclung
- Dennis Teefy
- J. S. Mcclung Jr.
- Patrick Mcdonnell
- Rick Fling
- William Burch