Unexploded ordnance (UXO) poses a threat to both human life and the environment. Millions of UXO may be located in the United States on active test and training ranges and on formerly used defense sites (FUDS). There may be as much as 30 million acres contaminated in more than 1,500 sites. Essentially all project investigations involve the use of digital geophysical mapping (DGM) to detect and locate buried UXO. One of the major challenges with DGM is accurate navigation for sensor position. This is especially problematic in vegetation and under tree canopies. Accurate, inexpensive, and easy-to-use navigation systems with consistent quality are needed for surveys in all terrain and vegetation cover. Navigation accuracy is essential for effective DGM.

The primary objective of the demonstrations was to determine the applicability of ENSCO’s Ranger positioning technology to support in-the-woods navigation as well as terrain-obstructed geophysical mapping activities. These are applications where the differential global positioning system (DGPS) is ineffective or has greatly reduced accuracy.

Demonstrations consisted of navigation equipment fully integrated with a Geometrics 858 cesium vapor magnetometer or a Geonics EM-61 electromagnetic metal detector. The initial focus was on acquiring high accuracy, fixed point navigation and large area data mapping by integrated navigation and geophysical sensor equipment. Selected anomalies from a dig list were reacquired to verify ability and accuracy in reacquisition.

The system was evaluated on the navigation positions as recorded for the known and unknown surface control points and on dig list locations for unknown subsurface anomalies. Surface points were separately evaluated for acquired position from the navigation equipment, from sensor profiles, and by the selected position from the gridded geophysical data’s anomaly representation.

Demonstration results show that Ranger navigation technology:

• Is easy to set up and use with minimal training
• Is integrated with Geometrics G-858 magnetometer and Geonics EM-61 electromagnetic metal detector
  
   
• Provides approximately 20 cm positioning accuracy (1 σ) in minimally cluttered outdoor environments, approximately 50 cm positioning accuracy (1 σ) in heavily wooded terrain
   
• Has a range of operation >1 km in minimally cluttered outdoor environments, >120 m in heavily wooded terrain
  
   
• Is effective as an advance prototype but requires further modification for robust field use
  
   
•  Is sensitive to the method used to locate fixed-location radios.

The demonstration documented the accuracy of Ranger navigation technology integrated with industry standard geophysical sensors. Results of the demonstration provide end users an understanding of the technical, logistical, and financial impact and allow informed decision making for appropriate applications.