The Common Time Module, a Robust Time Maintenance System

Andrew Dowd and R. Michael Garvey

Abstract:	The Common Time Module (CTM) is being developed by Symmetricom with support from the US Army/CERDEC. The goal is to implement timing services for mobile systems that demand a high degree of reliability and precision. The system is based around a core module that implements a time and frequency server with provisions for legacy time protocols. To address the rigors of a mobile and dynamic environment, the CTM manages multiple connections to the common time reference (UTC-USNO). Either GNSS signals (GPS) or a network connection (IEEE-1588) can synchronize local time services. In addition, the CTM integrates a low-power atomic resonator for extended holdover capabilities. By dynamically managing these technologies, the CTM can supply accurate time and frequency in a wide range of deployment scenarios. Furthermore, improvements in low-power technology such as ChipScale-Atomic-Clock (CSAC) will dramatically reduce power requirement, which is a significant advantage to mobile systems. Finally, this paper will examine how standardized IEEE-1588 network techniques will be applied to support redundancy with the CTM.
Published in:	Proceedings of the 41st Annual Precise Time and Time Interval Systems and Applications Meeting November 16 - 19, 2009 Hyatt Regency Tamaya Resort Santa Ana Pueblo, New Mexico
Pages:	33 - 44
Cite this article:	Dowd, Andrew, Garvey, R. Michael, "The Common Time Module, a Robust Time Maintenance System," Proceedings of the 41st Annual Precise Time and Time Interval Systems and Applications Meeting, Santa Ana Pueblo, New Mexico, November 2009, pp. 33-44.
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