Apparent Correlation of the Global Positioning System Y-Bias to the Divergence Between Timescales

Steve Deines

Abstract:	The Global Positioning System (GPS) exhibits precision navigation that has never before been attained. With such precision, small effects that formerly were lost in the noise levels of measurements are beginning to surface as systematic errors that are no longer random. The Y-bias is one such empirical term in GPS, which this paper claims may correspond to an external difference in timescale rates. The Y-bias is modeled as an empirical force term that allows the GPS predicted ephemeris to agree with the GPS satellite observations. This paper recommends that a comparison study be made from the following methods: (1) compute a predicted ephemeris without Y-bias using a smoothed Universal Timescale and (2) calculating a predicted ephemeris with Y-bias using the International Atomic Timescale with no leap second adjustment. This comparison would have no leap second and no weekly epoch adjustments. This test would show if the timescale deviation is the major cause for the Y-bias effect.
Published in:	Proceedings of the 10th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1997) September 16 - 19, 1997 Kansas City, MO
Pages:	1107 - 1111
Cite this article:	Deines, Steve, "Apparent Correlation of the Global Positioning System Y-Bias to the Divergence Between Timescales," Proceedings of the 10th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1997), Kansas City, MO, September 1997, pp. 1107-1111.
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