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Long-term instability in UTC time links



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 [1].
Conference Dates
January 31-February 2, 2017
Conference Location
Monterey, CA
Conference Title
Proceedings of PTTI 2017


CCD, DCD, GNSS, Stability, Time link, Time transfer, TWOTT, TWSTT, Uncertainty, UTC


Zhang, V. , Matsakis, D. and Jiang, Z. (2017), Long-term instability in UTC time links, Proceedings of PTTI 2017, Monterey, CA (Accessed April 14, 2024)
Created January 31, 2017, Updated July 3, 2017