MGEX和iGMAS的多系统轨道和钟差产品精度分析

采用分析中心间互比、SLR残差检核、卫星钟差拟合以及阿伦方差等方法对MGEX和iGMAS提供的多系统轨道和钟差产品精度进行综合分析。结果表明,GPS和GLONASS卫星的轨道精度分别在1.0～1.3cm和2.0～3.6cm,其中iGMAS提供的轨道产品较优。Galileo卫星的轨道一致性在10～17cm,采用ECODE2模型或附加先验模型可有效提高轨道精度。BDS GEO卫星的轨道一致性在数m级,径向精度约为25cm;IGSO和MEO卫星的轨道一致性分别在21～40cm和11～18cm左右,且径向精度分别优于10cm和5cm。MGEX和iGMAS提供的GPS和GLONASS卫星的钟差精度较好,但稳定性和可靠性仍有待提升。Galileo卫星的钟差一致性约为0.2～0.4ns,且钟差产品中吸收了未被模型化的轨道误差。BDS GEO、IGSO和MEO卫星的钟差一致性分别在0.35～0.46ns、0.25～0.33ns和0.11～0.21ns,其中CODE提供的BDS IGSO/MEO卫星的钟差产品受偏航姿态模式影响较大。

Precise Orbit and Clock Products for Multi-GNSS System from MGEX and iGMAS

Precise orbit and clock products for GPS, GLONASS, Galileo and Beidou from IGS MGEX and iGMAS are evaluated in this paper. Comparison among individual analysis centers (ACs), SLR validations, clock polynomial fitting and Allan deviation are utilized to analyze the characteristics of precise orbit and clock products from each ACs. The results show that: the orbit accuracy of GPS and GLONASS is about 1.0~1.3 cm and 2.0~3.6 cm, respectively; the GPS and GLONASS orbit products from iGMAS are better than other ACs’. For the Galileo system, the orbit agreement is about 10~17 cm in general; use of ECOM2 or a prior model can improve orbit quality. For the BDS system, the orbit agreement is about 21~40 cm for IGSOs, 11~18 cm for MEOs, and the radial accuracy is better than 10 cm and 5 cm respectively. However, GEO orbits have the worst agreements, having a few meters differences and radial errors of about 25 cm. Clock agreement is 0.2~0.4 ns for Galileo, 0.35~0.46 ns for BDS GEOs, 0.25~0.33 ns for BDS IGSOs, and 011~0.21 ns for BDS MEOs. The BDS IGSOs and MEOs’ clock products from CODE are markedly influenced by the yaw-attitude mode.