Development of time comparison equipment for ETS-VIII satellite

Engineering Test Satellite VIII (ETS-VIII) is planning to be launched in 2005 for fundamental studies on satellite positioning technologies and is the one first to have installed a highly precise cesium clock in Japan. To measure the clock offset between the satellite and the TCE earth station, Time Comparison Equipment (TCE) has been developed by NICT. The TCE will be used to measure both code and carrier phases and this system will improve two-way time and frequency transfer. This equipment makes it possible to compare two clocks with high precision. Moreover, TCE and TCE earth stations have abilities to remove the delay caused by terrestrial ionosphere and that between the receivers and transmitters. We estimated measurement precision in code and carrier phases. Furthermore, from the examinations using TCE-EM (Engineering Model), we confirmed that TCE is able to measure the clock phases with a subnanosecond precision by code phase observation and a precision of a few picoseconds by carrier phase observation. (C) 2006 Wiley Periodicals, Inc.