The Steering of GPS Time

H. F. Fliegel

Abstract:	The Navstar Global Positioning System (GPS) will be one of the most widely available means by which to distribute exact time. By agreement between the GPS Control Segment and the US Naval Observatory (USNO), GPS time will be maintained an integral number of seconds, n, from UTC, with an error less than or equal to one microsecond: T = GPS-UTC-n 31 sec, where n is the number of leap seconds which will have elapsed between early 1980 and current time. The GPS Navigation Message will give the value of T to 100 nanoseconds or better, real time. After the fact, values of the GPS-UTC offset should be available to qualified users with accuracy of 20 nanoseconds or better. GPS time will be steered by altering its adopted offset bias and drift from a Reference Clock. This paper summarizes the mathematics of the steering algorithm, and the interface between the US NO and the GPS Controller.
Published in:	Proceedings of the 15th Annual Precise Time and Time Interval Systems and Applications Meeting December 6 - 8, 1983 Naval Research Laboratory Washington, DC
Pages:	249 - 267
Cite this article:	Fliegel, H. F., "The Steering of GPS Time," Proceedings of the 15th Annual Precise Time and Time Interval Systems and Applications Meeting, Washington, DC, December 1983, pp. 249-267.
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