부산대학교 도서관

The Precise Timing Facility (PTF) is considered as a key element of the Ground Mission Segment (GMS) in the Galileo Global Navigation Satellite System (GNSS). The PTF major purpose is to generate the physical time scale of Galileo, the Galileo System Time (GST) with two main functions: the provision of a very stable time reference for navigation purposes and the metrological timekeeping. The first one is critical for fulfilling the navigation mission and is needed for the accurate computation of the orbit and satellite clock information included in the Galileo Navigation Message. The second function is aimed at steering GST towards International Atomic Time (TAI) and to provide the UTC timing dissemination service to the user. Navigation timekeeping is the core task of the PTF, whereas the metrological timekeeping is performed by an external Time Service Provider (TSP). In addition to the above, PTF is also in charge of computing the Galileo-GPS Time Offset (GGTO) which allows the combined use of signals from both GNSS. Both identical PTFs are hosted at the Galileo Control Centres (GCC) in Fucino (Italy) and in Oberpfaffenhofen (Germany). The Italian PTF has supported the Galileo Operations of In-Orbit Validation phase (IOV) until the second part of 2013 while the redundant unit located in Germany will be completely qualified at the end of this year. This paper reports the first performance results of the PTF in Fucino (Italy) after the initial In-Orbit Validation (IOV) phase.