北斗三号MEO卫星非保守力建模

Modeling non-conservative forces for BDS-3 MEO satellites

非保守力模型精度不高是制约BDS-3卫星定轨精度的主要因素之一。本文针对BDS-3 MEO卫星构建了地球辐射、天线辐射和箱体-两翼(BW)太阳光压模型,对典型的经验光压模型(ECOM1和ECOM2)进行补偿得到多个非保守力模型,收集全球观测网的数据进行定轨试验,通过轨道重叠互差和激光测距残差分析比较不同轨道模型的优劣。试验结果表明,经验光压模型是影响轨道精度的主要因素,在名义偏航模式下,ECOM2具有更好的表现,但ECOM1对卫星的姿态模式更不敏感。地球辐射和天线辐射会引起北斗卫星轨道径向约3 cm的系统性偏差,对二者建模后,几乎可以完全消除卫星C29和C30的激光残差系统偏差,但卫星C20和C21的系统偏差反而增大。此外,增加box-wing模型对于提高轨道精度也是有益的。

The non-conservative force(NCF)model is one of the main factors that restrict orbit accuracy of BDS-3 satellites.In this paper,several NCF models for BDS-3 MEO satellites were built by compensating typical empirical solar radiation pressure(SRP)models,i.e.,the ECOM1 and ECOM2,with earth radiation pressure(ERP),antenna thrust(AT)and the box-wing SRP model.Experiments were carried out with globally distributed stations to compare different NCF models by analyzing the overlap orbit differences and SLR residuals.It s shown that the empirical SRP modes dominate the orbit precision and the ECOM2 is superior to ECOM1 under the nominal yaw steering(YS)mode,while the ECOM1 is less sensitive to different YS modes.The ERP and AT together cause a systematic deviation of about 3 cm in the radial direction of orbit.By modeling the ERP and AT,the SLR residuals bias of satellites C29 and C30 can be almost completely eliminated,but the bias of satellites C20 and C21 increases.In addition,introducing the box-wing model is also beneficial to improve the orbit accuracy.