Simulation and Ground Experiments of Remote Synchronization System for Onboard Crystal Oscillator of Quasi‐Zenith Satellite

: The quasi-zenith satellite (QZS) system (QZSS) is a Japanese project that was started in 2003 with the aim of positioning services. A simulation and experiment on a new timekeeping method for the QZSS was conducted on the ground. The remote synchronization system for the onboard crystal oscillator (RESSOX) of the QZS functions by maintaining an uplink to receive time information from a ground station (GS) equipped with accurate atomic clocks. The required apparatuses for the RESSOX are described. Some simulation and experimental results obtained on the ground, which indicate the feasibility of synchronization to within 10 ns between the GS and the QZS, are demonstrated and compared.