导航卫星自主定轨星座旋转误差的地面校正算法

A Correction Algorithm of Constellation Rotation Error in Autonomous Navigation Using Ground Stations

基于星间测距的导航卫星自主定轨不可避免地会出现星座旋转,导致轨道精度下降并对造成用户定位系统误差。对星座旋转现象的原因和影响进行了分析,指出轨道升交点赤经的系统偏差ΔΩ和地球定向参数EOP的预报误差是星座旋转的主要误差源,主要表现为星座绕地球自转轴(Z轴)的旋转。在此基础上,提出一种独立、实用的星座旋转的地面校正算法,利用区域地面站的伪距观测值估计并校正星座旋转误差。仿真结果表明,使用两个测站可以估计旋转误差的三个分量,较为完善地消除星座旋转误差,显著提高用户定位的精度;使用一个测站,仅考虑关于Z轴的旋转分量,也可以校正大部分旋转误差,但校正效果略差。

Constellation rotation will inevitably occur when navigation satellites operated in autonomous navigation（AutoNav）mode using inter-satellite ranging measurements.It will reduce ephemeris accuracy and cause systematic errors in users＇ positioning.This paper quantifies the constellation rotation error and its effects.The analysis indicates that the major sources of rotation error,which mainly cause constellation rotation about the earth＇s axis（Z-axis）,are longitudes of ascending nodes bias（ΔΩ）and earth orientation parameters（EOP）prediction errors.On this basis,this paper presents a correction algorithm for estimating and eliminating the rotation error by using pseudo-range measurements from regional ground stations.It can be established easily and independently of the AutoNav system.Simulation results show that：1）all three components of the rotation can be estimated and eliminated by using two stations base on this algorithm,greatly improving positioning accuracy;2）with only one single station and considering only the Z-axis component of the rotation,the algorithm is still effective and errors can be corrected with a slightly reduced performance.