测绘学报 ›› 2021, Vol. 50 ›› Issue (12): 1728-1737.doi: 10.11947/j.AGCS.2021.20210084

• 导航卫星系统 • 上一篇    下一篇

北斗三号星座拟稳钟差测定及其预报

杨宇飞1, 杨元喜2,3, 陈金平1, 唐成盼4, 李冲1, 郭海荣1, 杨建华4, 刘金获4, 杨斌1   

  1. 1. 北京卫星导航中心, 北京 100094;
    2. 地理信息工程国家重点实验室, 陕西 西安 710054;
    3. 西安测绘研究所, 陕西 西安 710054;
    4. 中国科学院上海天文台, 上海 200030
  • 收稿日期:2021-02-22 修回日期:2021-08-20 发布日期:2022-01-08
  • 通讯作者: 杨元喜 E-mail:yuanxi_yang@163.com
  • 作者简介:杨宇飞(1992—),男,博士,工程师,研究方向为GNSS精密定轨及时间同步。

Pseudo-stable constellation bias error of BDS-3 and its high-precision prediction

YANG Yufei1, YANG Yuanxi2,3, CHEN Jinping1, TANG Chengpan4, LI Chong1, GUO Hairong1, YANG Jianhua4, LIU Jinhuo4, YANG Bin1   

  1. 1. Beijing Satellite Navigation Center, Beijing 100094, China;
    2. National Key Laboratory of Geo-information Engineering, Xi'an 710054, China;
    3. Xi'an Research Institute of Surveying and Mapping, Xi'an 710054, China;
    4. Shanghai Astronomical Observatory, Shanghai 200030, China
  • Received:2021-02-22 Revised:2021-08-20 Published:2022-01-08

摘要: 北斗三号卫星搭载了Ka波段星间链路载荷,可实现卫星之间的测距与通信。将星座内所有卫星的原子钟视为一个钟组,利用星间双向观测实时测量钟组内部时差,选取部分较为稳定的钟作为基准钟,可以建立星座拟稳原子时,得到各卫星的星座拟稳钟差,再通过少量链路向BDT溯源,即可最终得到卫星相对于BDT的钟差。以星座拟稳时间为观测量进行星载原子钟性能及钟差预报精度分析,可以避免卫星轨道误差对于钟差的影响,得到更加真实可靠的分析结果。试验结果表明:北斗三号星载原子钟,尤其是氢原子钟,具有良好的稳定性,MEO卫星氢原子钟天稳哈达马方差为3.5E-15,IGSO卫星氢原子钟为2.8E-15,铷原子钟为8.2E-15;星座拟稳钟差1 h预报误差RMS约为0.1 ns,可有效分离钟差预报误差和时间溯源误差,使北斗三号空间信号精度达到甚至优于15 cm。显然,星间链路的巨大潜力有待进一步挖掘。

关键词: 北斗三号, 原子钟, 星间链路, 拟稳, 频率稳定性, 钟差

Abstract: The BDS-3 satellite is equipped with Ka-band inter-satellite link (ISL) payload to realize ranging and communication between satellites. By taking all the spaceborne atomic clocks of the constellation as a group, the clock error within the group can be measured in nearly real-time by ISL. With some of the more stable clocks as the reference, the constellation pseudo-stable atomic timescale can be established. The deviation between the constellation pseudo-stable clock and the BeiDou time (BDT) can be obtained using only one or a few ground stations. The performance of the spaceborne atomic clock and the accuracy of the clock prediction can be obtained using the pseudo-stable constellation clock errors, which avoids the influence of the satellite orbit error on the clock error estimation and can get more realistic and reliable analysis results. The results show that the spaceborne atomic clocks of the BDS-3, especially the passive hydrogen maser (PHM), have good stabilities. The average Hadamard deviation with an integration time of 1 day is 3.5E-15 for MEO satellite PHM, 2.8E-15 for IGSO satellite PHM and 8.2E-15 for MEO rubidium atomic frequency standards (RAFSs). The RMS of 1 hour prediction error of the constellation pseudo-stabilized clock bias is about 0.1 ns, which can improve the BDS-3 signal in space accuracy to even better than 15 cm. Obviously, the huge potential of ISL needs to be further explored.

Key words: BDS-3, atomic clock, inter-satellite link, pseudo-stable, frequency stability, clock bias

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