ION Technical Content
GPS-Like Navigation Underground
| Abstract: | Navigation systems based on GNSS do not function in underground environments where multi-path is severe and signals do not penetrate. Magnetic near-fields, on the other hand, have no multi-path and can penetrate deep within the earth. For decades, scientists and engineers have located buried magnetic dipoles by following the field lines back to the source, which gives the horizontal location of the source. While some work exists for determining source depth, the methods are somewhat ad-hoc and require additional measurements to be made after physically moving the receiver (magnetometer) to the source horizontal location. While this research gives tremendous insight into dipole fields and their utility, current geo-location methods using magnetic near-fields do not allow GPS-like navigation. Through the DARPA/STO Subsurface Navigation (SsN) program, a system based on magnetic dipoles has been shown to provide GPS-like navigation in an underground environment. Unlike previous work where the transmitter is buried, magnetic dipoles are placed on the surface. These dipoles are then electrically rotated. Analysis of the rotating dipole fields detected by the underground magnetometer provides a geometry that uniquely determines the magnetometer location relative to the beacons. With no more underground hardware than a magnetometer and its electronics, a computing platform, and a power supply, the user location can be found in real time over a region defined by the beacon locations. The user is allowed to translate/rotate throughout the measurement process. Unlike previous work where only horizontal location is easily found, the SsN system generates full 3D position estimates. User orientation is also estimated from the dipole signals without measuring magnetic north or gravity. This paper provides multiple examples of underground, GPS-like navigation collected during system testing. |
| Published in: |
Proceedings of IEEE/ION PLANS 2010 May 4 - 6, 2010 Renaissance Esmeralda Resort & Spa Indian Wells, CA |
| Pages: | 1108 - 1111 |
| Cite this article: | Davis, C., "GPS-Like Navigation Underground," Proceedings of IEEE/ION PLANS 2010, Indian Wells, CA, May 2010, pp. 1108-1111. https://doi.org/10.1109/PLANS.2010.5507196 |
| Full Paper: |
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