Algorithm Considerations for GPS Meteorology in a Military Environment

David A. Garay, John F. Raquet and Mikel M. Miller

Abstract:	Over the past few years, the field of GPS meteorology has made great strides. Numerous groups have demonstrated the ability to use GPS receiver networks to estimate precipitable water (PW) over a regional area. Normally, these demonstrations are performed in a civilian context, where even receiver spacing with very few gaps is assumed. This paper analyzes PW estimation algorithms under less favorable conditions, like those that would be encountered in a military environment. In particular, a scenario is tested in which there is a large “hole” in the center of the receiver network. This represents the situation that would occur when PW estimation is desired, but there is a large geographical region where GPS receivers cannot be placed (such as in hostile territory). Real GPS data from a 1000km x 1000km, 18 receiver GPS meteorology network is used to analyze the effects of a degraded GPS receiver network (with a large gap in the middle) on PW estimation accuracy. Additionally different interpolation algorithms are applied to the gap region, and interpolation accuracy is assessed. The improvement obtained by placing just one receiver in the middle of the gap region is analyzed. Finally, the effects of varying levels of ephemeris accuracy on the PW estimation algorithms are considered. The results show that, surprisingly, a large gap in the middle of the network (reducing it to a 7 receiver network) did not significantly degrade the PW estimation accuracy for the remaining receivers. However, the interpolated results in the middle of the gap showed up to an 8mm RMS PW interpolation error. Placing a single receiver in the middle of the gap improved the accuracy near that receiver. Additionally, the results were not highly sensitive to the type of interpolation algorithm used. Suggestions for future research and algorithm development are presented.
Published in:	Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002) September 24 - 27, 2002 Oregon Convention Center Portland, OR
Pages:	1900 - 1909
Cite this article:	Garay, David A., Raquet, John F., Miller, Mikel M., "Algorithm Considerations for GPS Meteorology in a Military Environment," Proceedings of the 15th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2002), Portland, OR, September 2002, pp. 1900-1909.
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