基于精密点定位PPP的基本原理,介绍了利用观测值历元间差分的运动学精密定轨的方法.相比经典的动力学精密定轨,运动学精密定轨不受重力场模型、大气阻力、太阳光压等摄动力的影响,因而对于重力场恢复等研究具有较大帮助.并对两个星期CHAMP、GRACE的观测数据进行了分析.与参考轨道的对比表明,CHAMP的运动学轨道与参考轨道在XYZ 3个分量上差值中误差的平均值为0.22 m、0.22 m、0.25 m,三维中误差平均值为0.41 m;GRACE-A卫星的运动学轨道与参考轨道在XYZ 3个分量上差值中误差的平均值为0.27 m、0.23 m、0.29 m,三维中误差平均值为0.45 m.
on the basis of the theory of Precise Point Positioning ( PPP), a kinematic algorithm POD ( Precise Orbiter Determination) based on an epoch-wise processing of the code observations combined with an epoch - differeee processing of the phase observations is introduced. The method allows recovering the trajectory of the LEO without making use of any a priori dynamic perturbation, e. g. , gravity field information and air drag, it may be very useful for gravity field recovery. Experiments with CHAMP and GRACE observations over a period of 2 weeks show that kinematic orbits of CHAMP have an average 3D RMS about 0.41m comparing to reference orbits, while the average 3D RMS of GRACE is 0.45 m,the average RMS of the 3 axes component (0.22,0.22,0.25) m are of CHAMP and (0.27,0.23,0.29) m of GRACE.