High Resolution Magnetic Characterization In Complex Settings: Two Case Studies

This paper describes the results of two separate deployments of the GPS navigated, high density magnetic<br>characterization system, STOLS. In both cases, complex cultural signatures from nearby structures contaminated<br>the magnetic field data and obscured the magnetic signatures of the buried targets. Specialized processing<br>techniques were required to determine the location and size of each target. The high density of the survey data (-25<br>samples I m* ) and the high quality of the sensor positioning via GPS allowed for the application of image and data<br>processing techniques. The first case comes from the Department of Energy Project Office in Grand Junction,<br>Colorado, where the location of buried 55 gallon drums was in question. The site was a small sensor test facility<br>adjacent to several buildings, powerlines and fences. Data was collected and filtered to produce a high spatial<br>frequency map of the facility. A 2D spatial correlation filter was applied to statistically rank all likely targets. The<br>second case comes from the Chocolate Mountain Aerial Gunnery Range, in southeastern California, where STOLS<br>was deployed to quickly and accurately detect and characterize, in terms of position, depth and size, all buried<br>unexploded ordnance. At Chocolate Mountain an 18 mile gas pipeline easement within the Aerial Gunnery Range<br>was successfully surveyed. The magnetic anomaly data collected along the easement were severely contaminated<br>by two existing pipelines, A new processing technique which isolates the signatures of ordnance items was<br>developed and applied to the data to remove the pipeline effect and reveal anomalies adjacent to the pipeline. This<br>technique enabled STOLS to detect and locate all UXO in the easement.