The Timing Group Delay (TGD) Correction and GPS Timing Biases

Demetrios Matsakis

Abstract:	The Timing Group Delay (TGD) is the bias difference between each GPS satellites P-code transmissions at the L1 and L2 frequencies. They are broadcast in the GPS navigation message so that single-frequency users can use them in conjunction with ionosphere delay estimates, such as the Klobuchar ionosphere model, to improve their position determination and to better derive UTC(USNO), which is the U.S. Naval Observatory’s realization of Coordinated Universal Time (UTC). There are at most a few nanoseconds of bias in the TGDs with respect to the official GPS monitor receivers maintained at the USNO. These are within the calibration uncertainties. This paper analyzes the problem, and outlines an approach to a solution.
Published in:	Proceedings of the 63rd Annual Meeting of The Institute of Navigation (2007) April 23 - 25, 2007 Royal Sonesta Hotel Cambridge, MA
Pages:	49 - 54
Cite this article:	Matsakis, Demetrios, "The Timing Group Delay (TGD) Correction and GPS Timing Biases," Proceedings of the 63rd Annual Meeting of The Institute of Navigation (2007), Cambridge, MA, April 2007, pp. 49-54.
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