The BeiDou Navigation Satellite System (BDS) is essentially a precise time measurement and time synchronization system for a large-scale space near the Earth. General relativity is the basic theoretical framework for the information processing in the master control station of BDS. Having introduced the basic conceptions of relativistic space–time reference systems, the space–time references of BDS are analyzed and the function and acquisition method of the Earth Orientation Parameters (EOP) are briefly discussed. The basic space reference of BDS is BeiDou Coordinate System (BDCS), and the time standard is the BDS Time (BDT). BDCS and BDT are the realizations of the Geocentric Terrestrial Reference System (GTRS) and the Terrestrial Time (TT) for BDS, respectively. The station coordinates in the BDCS are consistent with those in International Terrestrial Reference Frame (ITRF)2014 at the cm–level and the difference in scale is about $$1.1 \times 10^{ - 8}$$ . The time deviation of BDT relative to International Atomic Time (TAI) is less than 50 ns and the frequency deviation is less than $$2 \times 10^{ - 14}$$ . The Geocentric Celestial Reference System (GCRS) and the solar Barycentric Celestial Reference System (BCRS) are also involved in the operation of BDS. The observation models for time synchronization and precise orbit determination are established within the GCRS framework. The coordinate transformation between BDCS and GCRS is consistent with the International Earth Rotation and Reference Systems Service (IERS). In the autonomous operation mode without the support of the ground master control station, Earth Orientation Parameters (EOP) is obtained by means of long-term prediction and on-board observation. The observation models for the on-board astrometry should be established within the BCRS framework.

中文翻译：

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北斗卫星导航系统时空参考

北斗卫星导航系统（BDS）本质上是一种面向地球附近大尺度空间的精密测时和时间同步系统。广义相对论是北斗系统主控站信息处理的基本理论框架。介绍了相对论时空参考系的基本概念，分析了北斗系统的时空参考，简要讨论了地球定向参数（EOP）的功能和获取方法。北斗的基本空间参考是北斗坐标系（BDCS），时间标准是北斗时间（BDT）。BDCS 和 BDT 分别是 BDS 的地心地球参考系统 (GTRS) 和地球时间 (TT) 的实现。BDCS 中的台站坐标与国际陆地参考框架（ITRF）2014 中的坐标在厘米级一致，尺度差异约为 $$1.1 \times 10^{ - 8}$$ 。BDT相对于国际原子时（TAI）的时间偏差小于50 ns，频率偏差小于$$2 \times 10^{ - 14}$$ 。地心天体参考系统（GCRS）和太阳重心天体参考系统（BCRS）也参与了北斗系统的运行。在GCRS框架内建立了时间同步和精确定轨的观测模型。BDCS 和 GCRS 之间的坐标转换与国际地球自转和参考系统服务 (IERS) 一致。在没有地面主控站支持的自主运行模式下，地球定向参数（EOP）是通过长期预测和车载观测获得的。星载天体测量的观测模型应在 BCRS 框架内建立。