IAU2000决议对卫星轨道的影响

A Study of Satellite Orbit Differences under IAU2000 Resolution

研究了IAU2000对GPS卫星轨道确定的影响。以2006年DOY186的GPS数据为例,分析了GPS卫星在IAU2000决议模型以及原有模型下,惯性参考系统以及地固坐标系中轨道的差别。结果显示,采用不同模型,卫星轨道在惯性参考系中的差值存在周期性,其中X、Z方向的幅度达到了2.5 m,Y方向的幅度约为1 m;在地固系中,轨道差别也存在周期,幅度约为4 mm。并对卫星轨道的差值进行了统计,得出了在惯性系下,不同模型引起轨道差值的3D RMS为m级。

The IAU2000 resolution was adopted at the IAU 24th General Assembly in 2000. The new resolution has officially become effective since January 1,200a. Compared with the old system （FK5）, which was essentially derived from Newtonian Mechanics; the new system is kinematically defined by the position of the extragalactic radiosources. The two systems are mainly differenced in the definition of the pole, orientation and the models of transformation between celestial frame and terrestrial frame. As a matter of fact, implementing of the new resolution will affect the orbits of artificial satellites, whose trajectories are determined according to the ground observations. The paper describes in detail the impact on GPS orbits due to the introduction of the new models in IAU2000 resolution. GPS data on DOY 186 2005 are analyzed to find out the orbit difference between old and new models. Results show that orbits difference of GPS exhibit a periodical signal in either inertial systems or terrestrial frame, with an amplitude about 2.5 m at X, Z axis and 1 m at Y axis in inertial systems, while that is about 4mm in each axis in terrestrial system. Statistics of orbits difference show that the 3D RMS of orbits difference in inertial systems is around 3m, and the orbits difference is neglect able in terrestrial system.