Demonstration Experiments of Ressox Using “Michibiki”

Toshiaki Iwata, Kojiro Saito, Kumiko Machita, Takashi Matsuzawa, Takashi Kawauchi, Yoshiharu Fukuhara, Tamotsu Hiroshima, Kazuo Tokita, Tamaki Takahashi, Satoshi Horiuchi, Yasuhiro Takahashi

Abstract:	The first Quasi-Zenith Satellite (QZS) of Japan named “Michibiki” was launched on September 11, 2010. After the first three months of initial functional verification tests, demonstration experiments were started on December 13, 2010. Three kinds of demonstration experiments using Michibiki have been planned for RESSOX (Remote Synchronization System of the Onboard Crystal Oscillator): (1) experiments without onboard voltage-controlled ovencompensated controlled crystal oscillator (VCOCXO) control of Experiment One (Exploratory Experiments), (2) experiments with onboard VCOCXO control of Experiment One, and (3) experiments with onboard VCOCXO control of Experiment Two. In Experiment One, the RESSOX control signal that includes information of the standard time is sent from ground stations and the onboard crystal oscillators of QZS are controlled to synchronize the arrival of the RESSOX control signal. The RESSOX control signal is similar to such time calibration signals as WWV or JJY, but the delay is compensated. In Experiment Two, on the basis of the results of time comparison between the onboard VCOCXO and the ground standard time conducted by the National Institute of Information and Communications Technology (NICT), the voltage applied to the onboard VCOCXO is calculated at the ground station and transmitted to QZS to control VCOCXO. Demonstration experiments of (2) and (3) were performed in March, May, July, September, and November 2011, and will be performed in January 2012 for one week each. At the moment, the feedback control of Experiment One has been successfully confirmed; however, the synchronization error is approximately 1200 ns peak-to-peak. In Experiment Two, the synchronization error in the time comparison experiment of NICT is less than 0.3 ns for six days, which means that the performance is comparable to that of hydrogen masers. In this paper, the experimental results obtained so far by the demonstration experiments are presented and discussed.
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:	305 - 324
Cite this article:	Iwata, Toshiaki, Saito, Kojiro, Machita, Kumiko, Matsuzawa, Takashi, Kawauchi, Takashi, Fukuhara, Yoshiharu, Hiroshima, Tamotsu, Tokita, Kazuo, Takahashi, Tamaki, Horiuchi, Satoshi, Takahashi, Yasuhiro, "Demonstration Experiments of Ressox Using “Michibiki”," Proceedings of the 43rd Annual Precise Time and Time Interval Systems and Applications Meeting, Long Beach, California, November 2011, pp. 305-324.
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