Victor S. Zhang, Demetrios Matsakis, Zhiheng Jiang
Calibration and link stability are the key issues for the UTC time transfer. This study is made in the framework of a joint task group of the CCTF Working Group on TWSTFT and Working Group on GNSS Time Transfer to investigate the long-term instability of the UTC time transfer links and we present several recommendations under consideration. For a UTC time link, the stability is as important as the calibration. We investigate the site- based and link-based instabilities of UTC time transfer. Using the zero-baseline common clock difference analysis, we compare co-located GPS receivers that use common reference signals from the same clock to directly investigate the long-term instability of the individual C/A, P3 and PPP techniques. Using the double clock difference between separated UTC laboratories, we compare GNSS and TWSTFT time links to indirectly investigate the long-term instability of GPS C/A, P3, PPP, GLONASS L1C and TWSTFT over the period of 2011-2016. Our study is interested in the nanosecond level of instability, since the combined (statistical and systematic) calibration uncertainty of a TW link (using mobile TW station or GPS calibrator) is 1~1.5 ns and that of the GPS equipment calibration is 1.7 ns, cf. Circular T 345 .
January 31-February 2, 2017
Proceedings of PTTI 2017
CCD, DCD, GNSS, Stability, Time link, Time transfer, TWOTT, TWSTT, Uncertainty, UTC