星敏感器与地平仪联合自主定轨改进算法

Improved autonomous orbit determination algorithm using star sensor and earth sensor

针对星敏感器地平仪联合自主定轨算法在工程中不易应用及工程应用中定轨精度较低等问题,提出了一种改进的自主定轨算法。第一,调整算法观测量,利用惯性坐标系下地心矢量替代星光角距值作为Kalman滤波方程的观测量,以适应卫星星敏感器标准输出;第二,在算法中加入敏感器误差处理环节,包括对敏感器的常值误差进行求取,从而实现对地心矢量测量值的修正,以及用抗野值方法对尖峰噪声误差进行处理,从而消除尖峰噪声对Kalman滤波定轨算法的影响;第三,采用无迹Kalman滤波算法将具有新的观测量与敏感器误差处理环节的改进的天文导航算法加以实现。通过某在轨中轨道卫星数据校验表明,改进后的自主定轨算法定轨精度在千米量级,可在工程中有效实施。

To solve the application difficulty and the low accuracy problem in the engineering field, an improved autonomous orbit determination method using star sensor and earth sensor was proposed. First, the observation variable was changed. That is, to adapt the star sensor standard outputs, the geocentric unit vector of the inertial coordinate system instead of the starlight angular distance was taken as the observation variable in the Kalman filter equations. Second, an error elimination section was added into the method. Constant errors were calculated to correct the measured geocentric vector, and the spike noises were eliminated by the fault–tolerant improvement method. Third, the improved autonomous orbit determination method with the new observation variable and an error elimination process was implemented based on the unscented Kalman filter method. The verification teats through in-orbit data of a medium-earth-orbit satellite show that the orbit determination error is in the level of kilometers, and the proposed method can be effectively applied in the engineering field.