The National Time Service Center(NTSC) maintains the local realization of Coordinated Universal Time, UTC(NTSC), which is the reference for legal time services in CHINA. NTSC has made a lot of technology researches and equipment update these years. The performance of UTC(NTSC) has reached international advanced level, its divergence with respect to UTC has been kept stable within five nanoseconds during more than last three years.

 At present, NTSC maintains an ensemble of more than 30 commercial cesium clocks, and 11 hydrogen masers. They are under carefully controlled environmental conditions. The clocks data are input to a time scale algorithm, and then generates an independent time scale, called TA(NTSC). The computation of TA(NTSC) is carried out every month and the result is published in the Time and Frequency Bulletin monthly. Figure 1 is a graph of the frequency instability of TA(NTSC) in 2020, it indicates that the frequency instability of TA(NTSC) is about 8.3E-16(5 days) and 4.7E-16(30days).

Figure 1. Overlapping Allan Deviation of TAI-TA(NTSC) in 2020(Imaged by: NTSC)

UTC(NTSC) is generated by applying coordination adjustments to TA(NTSC) and UTC, Which is a real-time time scale that produce physical signals. UTC(NTSC) is the reference for Chinese time dissemination services, and a traceability reference  for BEIDOU time. In 2020, NTSC improved its time keeping system continuously and better results have been achieved. Figure 2 shows that the time difference between UTC and UTC(NTSC) in 2020.

Figure 2. Time Difference of UTC-UTC(NTSC) in 2020(Imaged by: NTSC)

CONTACT:

ZHAO Shuhong

National Time Service Centre

zsh@ntsc.ac.cn