Construction and Application of BeiDou Time System
China’s BeiDou satellite navigation system can already provide Position, Navigation and Time(PNT)services in the Asia-Pacific area at present. It is expected that a global system including 35 satellites will be built in 2020 to achieve global coverage. With the construction and steadily improvement of the Beidou system, its application in various fields is also being carried out. Because of its high-precise time reference and synchronization, the global navigation satellite system (GNSS) can realize the positioning, navigation, and timing functions precisely. Every GNSS has independent time reference system, called GNSST, and it is traced to the national official time UTC(k) whose divergence with respect to the Coordinated Universal Time (UTC) has been kept stable within several ns in most time. Based on the synchronization and unification of GNSST and international standard time UTC, its time service function is realized. The BeiDou system reference time, BDT, is traced to UTC through UTC (NTSC) which is maintained by National Time Service Center (NTSC), Chinese Academy of Science. In order to promote the development and application of BeiDou, NTSC implemented the BeiDou international common-view time comparison and got the preliminary result. It is proved that BeiDou can realize the long baseline precise time transfer. In this chapter, BeiDou system, BeiDou time international cooperation, the relationship between BeiDou time and UTC, development of time service of China, and the application of information system in time service work are introduced.
KeywordsBeiDou Information system Time transfer UTC Navigation and positioning Time service Traceability
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