Potential Ionospheric Limitations to Wide-Area Differential GPS

John A. Klobuchar, Patricia H. Doherty, M. Bakry El-Arini

Abstract:	Navigation and positioning using Wide-area Differ- ential GPS with single frequency receivers, (WDGPS) potentially suffers from the unknown spatial variabil- ity of ionospheric range delays (e.g., spatial gradients in ionospheric delays) between locations where dual frequency measurements from GPS satellites are being made. In a given large region, by deploying a sufficient number of dual-frequency GPS code and/or codeless receivers, it is possible to correct for most of the iono- spheric range delay using WDGPS real-time prediction algorithms. Using ionospheric data collected from a number of stations in North America the statistics of differences in range delay over station separations from approxi- mately 350 km to over 1,600 km are presented. During periods of high magnetic activity the ionospheric gra- dients are large, but these events are infrequent. For the mid-latitudes the goal is to keep ionospheric range delays to only a few meters for 95% of the time so that WDGPS can be used in precision approaches. This goal is easily attainable during solar minimum condi- tions, but may require more ground stations during periods of very high solar activity.
Published in:	Proceedings of the 6th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1993) September 22 - 24, 1993 Salt Palace Convention Center Salt Lake City, UT
Pages:	1245 - 1254
Cite this article:	Klobuchar, John A., Doherty, Patricia H., El-Arini, M. Bakry, "Potential Ionospheric Limitations to Wide-Area Differential GPS," Proceedings of the 6th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1993), Salt Lake City, UT, September 1993, pp. 1245-1254.
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