Characteristics of Satellite-Satellite Single Difference Widelane Fractional Carrier Phase Biases

Michael J. Gabor and R. Steven Nerem

Abstract:	Satellite-satellite single difference widelane fractional phase bias calibration values were analyzed for long term characteristics between January 1, 1997, and May 30, 1998. The calibration values were calculated by forming single difference widelane linear combina- tions of code and carrier phase measurements. By differencing between two GPS satellites and one re- ceiver, any receiver effects on the measurements can- cel. By differencing the widelane code and phase mea- surements, the geometric information, first-order iono- spheric effects, and the non-dispersive effects of the at- mosphere cancel. The resulting quantity isolates the widelane ambiguity term. This ambiguity term consists of an integer te.rm that is unique for each phase connected arc and a fractional term that is consistent for each single difference satel- lite pair. These fractional terms were then averaged over a global tracking network using directional statis- tics to calculate daily fractional i)hase bias calibration "values. Over the year and a half test period, the widelane single difference daily fractional phase biases experi- enced drifts, second order effects, and periodic sig- nals. Satellites 22, 26, 27, 29, 31, and 32 experi- enced near zero drift rates and signals with amplitudes smaller than 0.1 widelane cycles. Satellites 30, 33, and 40 had high drift rates between 0.78 and 1.4 wide- lane cycles/year and substantial second order signals. These groupings indicate a strong correlation with mis- sion date, possibly indicating a previously undiagnosed "settling in" period.
Published in:	Proceedings of the 13th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 2000) September 19 - 22, 2000 Salt Palace Convention Center Salt Lake City, UT
Pages:	396 - 406
Cite this article:	Updated citation: Published in NAVIGATION: Journal of the Institute of Navigation
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