Ensemble AT1 Ensemble Timekeeping for a Satcom System

James Camparo and Travis Driskell

Abstract:	We discuss the application of NIST’s AT1 ensembling algorithm to a communication satellite system. Whereas nanosecond timekeeping levels are required for global navigation satellite systems (GNSS), only microsecond timekeeping levels are generally required for satellite communications systems (Satcom systems). Regarding precise timekeeping, the challenge is that the workloads of Satcom system architectures are typically not designed for GNSS levels of precise timekeeping. Here, we explore the viability of NIST’s AT1 ensembling algorithm for a Satcom system employing rubidium atomic frequency standards (RAFS). Advantages to ensembling include greater timekeeping stability for the constellation, and greater reliability of system time in the event of satellite clock failures or constellation fragmentation. In the present paper, we consider the effects of different quality atomic clocks on a nominal Satcom system, and different levels of frequency correction quantization. Our results suggest that satellite clock ensembling is a viable approach for Satcom system timekeeping.
Published in:	Proceedings of the 50th Annual Precise Time and Time Interval Systems and Applications Meeting January 28 - 31, 2019 Hyatt Regency Reston Reston, Virginia
Pages:	168 - 176
Cite this article:	Camparo, James, Driskell, Travis, "Ensemble AT1 Ensemble Timekeeping for a Satcom System," Proceedings of the 50th Annual Precise Time and Time Interval Systems and Applications Meeting, Reston, Virginia, January 2019, pp. 168-176. https://doi.org/10.33012/2019.16751
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