采用重置参数的轨道改进算法

An Improved Method of Precise Orbit Determination by Resetting Model Parameters

当使用精度差的初始根数作定轨计算时,被估值的模型参数会吸收初值中所含误差而偏离其合理数值(如CD约为2.2),使定轨计算过程的RMS已不再变化,但轨道收敛到与实际状态有偏离的轨道上。文中给出的算例采用重置被歪曲的估值模型参数方法,首先以TLE根数为初值用精密定轨程序解条件方程,然后以第一轮迭代计算结果作为初始根数并重置模型参数,再进行第二轮迭代计算,使定轨计算结果收敛到正确轨道上,文中还使用另一颗激光卫星的双行根数作初值验证了该方法的有效性。较好地解决了因初值不准所引起的定轨计算不收敛,或收敛到与实际状态有偏离的轨道上的问题。最终得出的RMS达到厘米级精度。文中图示了两次定轨计算的RMS变化曲线图、残差分布图,迭代过程的资料采用率及定轨计算结果。

When using initial orbit elements with poor precision to calculate orbit elements of spacecrafts the model parameters（e, g. CD which is about 2. 2）estimated will be affected by the deviations in the initial elements, so that even if the RMS errors appear to converge the results of orbit do not converge to precise values. We give a method to reset the distorted parameters and also an example of its application to a satellite. A precise orbit-determination algorithm is used first to solve the conditional equations with the TLE as initial elements. The results are reset as the initial orbit elements for a new round of calculations, which converges to precise results. We further verify the method with the data of another satellite. The method thus has overall solved the problem that the calculation does not converge or converges to incorrect values due to the imprecise initial orbit elements. The RMS errors of the method reach the centimeter level. We show the RMS variation/distribution curves of two rounds of calculations, data use rates, and the results of orbit elements.