Research Divisions

High-precision Time Transfer and Precise Orbit Determination

Author:       ArticleSource:       Update time:2021/08/11

Research direction & platform:

The group's research interest mainly includes high-precision time and frequency transfer, precise orbit determination (POD), and related research questions. It contains:

1)Two-way satellite time and frequency transfer (TWSTFT) and orbit determination by transfer tracking (ODTT). The group carried out research on TWSTFT and ODTT, and developed its multi-station system platform within China.

2)POD and timing services based on BDS, other GNSSs and LEO satellites. The group developed a domestic tracking network, a data center and an analysis center for the International GNSS Monitoring & Assessment Service (iGMAS). The research of the group also includes the POD and clock determination for satellites of BDS, other GNSSs and those on LEOs; Positioning, timing and integrity monitoring using LEO and GNSS satellites; Modelling of the ionospheric and tropospheric delays; High-precision timing and time transfer based on GNSS satellites; Length of day (LOD) variations and pole shifts.

3)VLBI time transfer, orbit determination and related research. The group developed astrometric and geodetic wideband VLBI systems consisting of 3 sets of 13 m antennas and the Xi’an Center. The group determines EOP parameters like the UT1, carries out research about VLBI observations from navigation satellites, VLBI time transfer, satellite interferometric time measurement and passive orbit determination, and experiments of VLBI deep space exploration.

4)SLR precise measurement and applications. The Lishan 1.05 m laser optical telescope is under development, mainly for scientific research of lunar laser measurement, EOP measurement, large planets and their ephemeris.

Research team and achievements:
The research group has now 26 researchers, including six professors, and three selected for the Youth Innovation Promotion Association of the Chinese Academy of Sciences. In addition, a number of foreign academicians and professors have been invited as guest professors. Good international cooperation and a joint training system for postgraduate students have been established.

In recent years, in the research direction of high-precision time transfer and satellite POD, the group has been supported by major projects of BDS satellite navigation, the National Natural Science Foundation, the 863 and the 973 projects of the Ministry of Science and Technology. At the same time, the group has won the first, the second, and other prizes of the Science and Technology Progress Award at the provincial and ministerial level.

Research platform: Lishan Observatory (Image by NTSC)