Carrier-phase TWSTFT experiments using the ETS-VIII satellite

The National Institute of Information and Communications Technology (NICT) has developed and tested carrier-phase two-way satellite time and frequency transfer (TWSTFT) as a next-generation technique applicable to greater distances and resulting in higher precision. A method different from that used for code-based TWSTFT is required for carrier-phase TWSTFT. We propose a new method based on variations of carrier phases for the propagation of signals.Using the ETS-VIII satellite launched by the Japan Aerospace Exploration Agency (JAXA) and the Time Comparison Equipment (TCE) system developed by NICT, carrier-phase TWSTFT experiments were carried out between two ground-based hydrogen masers separated by a baseline of 110 km. Our tests showed that the frequency difference between two hydrogen masers can be measured for averaging times larger than 1000 s and the precision of carrier-phase TWSTFT is about 100 times better than that of code-based TWSTFT.