基于平方根信息滤波的北斗卫星实时定轨方法

Real-time orbit determination of Beidou satellite based on square root information filtering

连续、稳定、高精度的实时卫星轨道产品是北斗国际化、规模化、智能化应用的重要前提.当前,北斗卫星导航系统(BDS)的实时精密轨道产品多基于“批处理解算+轨道预报”的超快速模式获得,存在连续性较差、稳定性较低、精度不高等问题.为此,本文采用平方根信息滤波(SRIF)方法对北斗卫星精密轨道进行实时逐历元解算.实验结果表明:相比于超快速定轨模式,基于实时滤波方法的轨道产品能够有效避免边界跳变,具有更好的连续性和稳定性;同时,实时滤波定轨方法能够显著提高BDS的轨道精度,其中中轨道地球卫星(MEO)和倾斜地球同步轨道卫星(IGSO)的三维轨道误差分别减小了46%和68%,卫星激光测距(SLR)检核精度也普遍优于预报轨道.

Continuous,stable and high-precision real-time satellite orbit products are essential for the international,scale and intelligent application of the BeiDou system.Current BDS real-time precise orbit products,which rely on“batch processing solution+orbit prediction”,suffer from poor continuity,low stability and low accuracy.Therefore,we introduce the square root information filtering method to perform real-time epoch-by-epoch solutions for the precise orbit of BeiDou satellites.Experimental results demonstrate that the BDS orbits generated by real-time filtering method outperform the ultra-rapid orbit products by effectively avoiding boundary jumps,improving continuity and stability.Moreover,the real-time filtering precise orbit determination method can significantly improve the orbit accuracy of BeiDou satellites,reducing the 3D orbit errors of MEO and IGSO satellites by 46%and 68%,respectively.Also,the validation by satellite laser ranging shows that the orbit accuracy of real-time filtering method is generally better than that of the predicted orbit.