Precise Time-Transfer Experiment Using Two-Way Carrier-Phase Method Planned for ETS-VIII Satellite
COMMUNICATIONS RESEARCH LAB TOKYO (JAPAN)
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A precise time and frequency transfer between the satellite-onboard atomic clocks and the ground reference clocks has been planned for the Engineering Test Satellite-VIII ETS-VIII under the collaboration between the Communications Research Laboratory CRL and the National Space Development Agency NASDA. We will show the plan and the status report of this experiment. ETS-VIII is a Japanese Geostationary Satellite, which will be launched in 2002. It has missions for mobile communication experiments and for precision timing experiments using atomic clocks in space. For the latter purpose, it will be equipped with two cesium-beam frequency standards, which were developed for GPS satellites. CRL is conducting the precise time-and frequency-transfer experiment between the cesium atomic clock on ETS-VIII and the ground reference clock. For this experiment, a special time-transfer system, which was proposed by CRL, is now under development. In this system, we adopt a two-way time transfer method with the use of the carrier phase information for the precise timing measurement. This system also provides a function of compensating the internal delay variations of the transmission pass and the receiving pass in both satellite and ground station for accurate time transfer. It will attain a precision better than 10ps on the measurement of the time difference between on-board standards and the ground reference clocks. We have completed the on-board engineering model equipment and are constructing the prototype flight model.
- Test Facilities, Equipment and Methods
- Unmanned Spacecraft