Statistics of Time Rate of Change of Ionospheric Range Delay

Patricia Doherty, Eric Raffi, John Klobuchar, M. Bakry El-Arini

Abstract:	The time rate of change of ionospheric range delay is a potential limitation in precise positioning using radio waves from Global Positioning System, (GPS), satel- lites in the single frequency c/a mode. Dual frequency GPS users with access to the p-code automatically cor- rect for the effects of both the ionospheric range delay and its rate of change. Single frequency GPS users can use a simple algorithm for ionospheric range de- lay to place an absolute scale on their measurements of c/a code minus carrier, to correct for the time rate of change of ionospheric range delay, but the inherent noisiness of the Ll code data can severely limit the single frequency ionospheric correction capability, es- pecially in removing the effects of the rate of change of ionospheric range delay. To investigate the statistics of ionospheric range- rate changes, dual frequency GPS data from stations in parts of the world representative of different iono- spheric conditions was obtained from the International GPS Geodynamics Service, (IGS), network, managed by the Jet Propulsion Laboratory, (JPL). Values of dual frequency, differential carrier phase were com- puted at one minute intervals and then were high pass filtered to remove long term changes. Relative iono- spheric range delay changes over time intervals of 1, 2, 5, and 10 minutes duration were then computed and the statistics of these rates of change of ionospheric time delay were compiled for different times of day, viewing direction, and various conditions of magnetic activity. The largest rates of change of ionospheric range delay were observed in the auroral region dur- ing periods of high magnetic activity.
Published in:	Proceedings of the 7th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1994) September 20 - 23, 1994 Salt Palace Convention Center Salt Lake City, UT
Pages:	1589 - 1598
Cite this article:	Doherty, Patricia, Raffi, Eric, Klobuchar, John, El-Arini, M. Bakry, "Statistics of Time Rate of Change of Ionospheric Range Delay," Proceedings of the 7th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1994), Salt Lake City, UT, September 1994, pp. 1589-1598.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In