Journal of Astronautics ›› 2018, Vol. 39 ›› Issue (9): 1013-1021.doi: 10.3873/j.issn.1000-1328.2018.09.009

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Precision Analysis of BeiDou Satellites Broadcast Ephemeris

MAO Ya, WANG Qian xin, HU Chao, HE Yi lei   

  1. 1. School of Environmental Science and Spatial Informatics, China University of Mining and Technology,Xuzhou 221116, China; 2. NASG Key Laboratory of Land Environment and Disaster Monitoring, China University of Mining and Technology, Xuzhou 221116, China
  • Received:2018-01-29 Revised:2018-05-30 Online:2018-09-15 Published:2018-09-25

Abstract:

In order to analyze the accuracy of the BDS broadcast ephemeris, the laser ranging and precise ephemeris are used as the reference to do some analysis. Since there is no BDS-3 experimental satellite precise ephemeris, this paper designs the DBS-3 experimental satellite precise orbit determination experiment with a 3-day arc, and the results show that the orbit and clock offsets accuracies are about 50cm and 2ns respectively. Then combined with the BDS-2 post precision satellites ephemeris obtained from the international GNSS monitoring & assessment system (iGMAS), to evaluate the accuracy of the BDS-3/BDS-2 ephemeris-clock and ephemeris-orbit, in order to evaluate the ephemeris-orbit more accurately, the SLR observation data is used as an external means to evaluate the BDS satellite ephemeris-orbit accuracy, the 1d RMS of the ephemeris-orbit and the STD of ephemeris-clock are counted, and the results show that most clock accuracies are better than 10 ns, the orbit accuracy is better than 5 m. In addition, in order to analyze the time-frequency performance of the ephemeris-clock, the frequency stability, the drift rate and the accuracy of the satellite clock offset are calculated. The experimental results show that the performance of the BDS-3 test satellites is generally better than that of the BDS-2. The performance indicators of the frequency accuracy, frequency drift rate and frequency stability calculated show that the BDS-3 satellite increases by 42.8%, 22.5% and 9.5% compared with the BDS-2.

Key words: SLR analysis, BeiDou broadcast ephemeris, Step by step method, Time frequency characteristics

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