The time service performance evaluation of GNSS

Time service of GNSS is the capability to make user to obtain UTC. A testing and evaluation method of GNSS time service performance is put forward in this paper. Using the UTC (NTSC) as the user's local time, through the GPS and Beidou multimode receiver signal, the time difference of UTC (NTSC) and UTC(k) broadcasted by GNSS is got, to amend the UTC (k) to UTC with the Circular T issued by BIPM, the complete time service is obtained. In order to evaluate the time service performance, the time difference of UTC(NTSC) and UTC is obtained with Circular T as a reference to be compared and analyzed with the time service results of GPS and Beidou. The results showed that the GPS traceability is slightly better than BDS. BDS is in the construction stage now, its traceability will improve with the further development of system.