Spacecraft Atomic Clock Flight Simulation and Test Station

H. Wang, J. C. Camparo, and G. Iyanu

Abstract:	In order to help satellite operators understand and resolve flight atomic clock issues, we have constructed a flight simulation and test facility to assess and investigate the behavior of flight-model atomic clocks in a simulated operational space environment. To date, this capability has been focused primarily on exercising the atomic clocks flown by Milstar and AEHF satellites. In this paper, without going into the requirements or capabilities of the Milstar/AEHF systems, we describe our test station and report on some recent results regarding the simulated space performance of Rb atomic frequency standards (RAFS). The “space segment” of the test station has two spacecraft clocks housed in vacuum chambers. Each clock’s DC power supply and bath-circulator controlled thermal plate simulates the satellite’s power bus and the satellite’s diurnal temperature variations, respectively. The “ground control” segment includes a multiple clock measurement system, and a data acquisition and command interface system. Not only can we measure each clock’s telemetry signals and output frequency while the clocks operate in vacuum, we are also able to send commands to each clock. For example, we can switch a RAFS between its “atomic-clock” mode and its “crystaloscillator-backup” mode, and we can command a frequency update to a RAFS in order to synchronize the clock while we monitor the effects of the command on the clock’s output frequency and telemetry. We believe that the capabilities of our simulation and test station will be of interest to the sponsors and attendees of the conference.
Published in:	Proceedings of the 43rd Annual Precise Time and Time Interval Systems and Applications Meeting November 14 - 17, 2011 Hyatt Regency Long Beach Long Beach, California
Pages:	341 - 352
Cite this article:	Wang, H., Camparo, J. C., Iyanu, G., "Spacecraft Atomic Clock Flight Simulation and Test Station," Proceedings of the 43rd Annual Precise Time and Time Interval Systems and Applications Meeting, Long Beach, California, November 2011, pp. 341-352.
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