Use of Helicopter Platforms for High Resolution, Low-Altitude Magnetic Field Mapping

Sky Research has developed new and innovative data collection and analysis methodologies based on deployment of an array total field magnetometer data from a helicopter platform. Facilitated through a Cooperative Research and Development Agreement (CRADA) with the US Naval Research Laboratory (NRL), this helicopter magnetometer (HeliMag) technology is used for creation of highresolution magnetic field anomaly maps. The focus of this work has been the characterization of former and active military facilities contaminated with unexploded ordnance (UXO). For the UXO application, the system is deployed at low altitudes, as low as 2 m, to maximize probability of detection of UXO. The system integrates an array of seven Cs vapor magnetometers, RTK GPS, and altimeters, producing high-fidelity maps at a rate of approximately 200 hectares per day. Data are processed and analyzed to produce an inventory of shallow subsurface targets, including UXO and other ferrous items. This HeliMag technology plays a central role in the Wide Area Assessment (WAA) of military facilities. In general, WAA mapping technologies can be classified into three types according to acquisition rate, feature resolution and data acquisition cost per unit area: High Airborne, Low Airborne, and Ground Systems. Helicopter-based magnetometer technology is a low airborne technology that provides highly efficient digital geophysical mapping for UXO with detection and feature discrimination capabilities approaching ground-based methods. HeliMag deployments are limited primarily by terrain, vegetation and on-site structures which affect safe low-altitude flight. HeliMag datasets are integrated with other WAA technologies, including LiDAR, large scale digital orthophotography and hyperspectral imaging datasets from high airborne systems. In addition to UXO applications, HeliMag technology is currently being extended to several other areas including infrastructure mapping and exploration.