Ground Experiments of Remote Synchronization for Onboard Crystal Oscillator of Quasi-Zenith Satellites - Use of Multiple Positioning Signals for Feedback Control

We have developed a new control method for the quasi-zenith satellite (QZS) remote synchronization system for the onboard crystal oscillator (RESSOX). The new method utilizes L1 and L2 positioning signals of the QZS system. We have proved that precise orbit prediction or estimation of delays such as those caused by the ionosphere and troposphere is not necessary to realize RESSOX technology. L1/L2/Ku-band signal delay caused by the ionosphere and other sources is calculated separately using RESSOX feedback control. The results of Ku-band delay are used to generate the appropriate control signal. The results show that synchronization within 2 ns between the ground-site atomic clock and the QZS site is achievable. We also confirmed that the crystal oscillator that has the same specifications as the actual onboard crystal oscillator could be controlled by the same method as the prototype in the test bed.
See also ADM002029. Presented at the Annual Precise Time and Time Interval (PTTI) Meeting (38th), held in Reston, VA, on 5-7 Dec 2006. Published in the proceedings of the meeting, p153-174, 2007. Prepared in cooperation with University of Tokyo, Japan; Space Engineering Development Company, Japan; and University of New South Wales, Australia. The original document contains color images.