伪随机脉冲先验值对低轨卫星简化动力学定轨精度的影响

低轨卫星简化动力学定轨中引入伪随机脉冲可有效提高定轨精度，但伪随机脉冲先验值（时间间隔、先验标准差）会影响伪随机脉冲估值大小，进而影响定轨精度。基于GRACE（Gravity Recovery and Climate Experiment）卫星轨道分析伪随机脉冲先验值对单天解简化动力学定轨精度的影响，实验表明，时间间隔从240 min减至6 min，先验标准差从1×10-4mm/s增至1×10-1mm/s，伪随机脉冲总的估值大小由1×10-2mm/s增至1×101mm/s，定轨精度从几十cm提高到2 cm；当先验标准差大于1×10-1mm/s，继续增加先验标准差，伪随机脉冲估值不变，定轨精度不再提高。因此，对于单天解轨道，时间间隔减小至6 min，先验标准差增至1×10-1mm/s，伪随机脉冲估值增大，定轨精度提高；继续增大先验标准差，伪随机脉冲估值不变，定轨精度不再提高。利用不同高度的Swarm卫星验证了该结论的有效性。

Impact of Pseudo-Stochastic Pulse Priors on LEO Reduced-Dynamic Orbit Accuracy

Pseudo-stochastic pulses can improve the accuracy of LEO reduced-dynamic orbit determination effectively, but the pseudo-stochastic pulse priors (i.e., time interval and a priori sigma) will affect the values of pseudo-stochastic pulse, thereby affecting orbit accuracy. In this paper, single-day GRACE orbit experiments based on reduced-dynamic method show that time interval decreases from 240 min to 6 min, a priori sigma increases from 1×10-4 mm/s to 1×10-1 mm/s, the total values of pseudo-stochastic pulse increases from 1×10-2 mm/s to 1×101 mm/s, and the orbit accuracy improves from tens of centimeters to 2 cm; when a priori sigma is greater than 1×10-1 mm/s, a priori sigma continues to increase, the values of pseudo-stochastic pulse remain unchanged and the orbit accuracy unimproved. Therefore, for single-day orbit solution, time interval is reduced to 6 min, a priori sigma goes up to 1×10-1 mm/s, the values of pseudo-stochastic pulse increases, the orbit accuracy improves; a priori sigma continued to increase, the values of pseudo-stochastic pulse keep unchanged, and the orbit accuracy is unimproved. Using Swarm orbit experiments of different heights can be used to verify the validation of the conclusion.