基于矢量观测的航天器分段信息融合定姿方法

针对基于MEMS(微机电系统)陀螺和CMOS APS星敏感器的集成惯性/星光姿态确定系统的低精度特点,研究了适用于该定姿系统的基于矢量观测的定姿算法.对于陀螺/星敏感器这种配置模式,有EKF(Extended Kalman Filter)、QUEST、最优REQUEST等几种适用的定姿算法.针对EKF和最优REQUEST算法的不同特点并结合确定性算法QUEST,以四元数为姿态参数,将姿态估计的EKF方法分别与QUEST算法和最优REQUEST算法进行了融合,提出一种分段信息融合的姿态估计器:陀螺漂移估计误差较大时,将EKF与QUEST结合,快速估计出陀螺漂移.当陀螺漂移误差减小到一定程度,再切换为EKF与最优REQUEST算法融合的双重滤波器.仿真比较结果表明,这种分段信息融合的姿态估计器既可以估计姿态参数也可以估计陀螺漂移,并能达到很高的定姿精度.

Two-segment information fusion attitude determination method for spacecraft from vector observations

The low precision characters of the integrated inertial/stellar attitude determination system consists of MEMS(micro electromechanical systems) gyros and CMOS APS star sensor.For this question,the methods of attitude determination from vector observations which suitable for this system were studied.There are several attitude determination methods suitable for the gyro/star-sensor configuration such as EKF,QUEST and optimal REQEUST.According to the different characters between the EKF and optimal REQUEST and together with the single-frame method QUEST,the quaternion was used as the attitude parameter.A two-segment attitude estimator was presented: when the estimated error of gyro drift was large,the fusion mode of EKF and QUEST was used to estimate the gyro drift as soon as possible.When the estimated error of gyro drift reduces to some low extent,the filter was switched to the fusion mode of EKF and optimal REQUEST.The results of simulation show that the two-segment estimator can estimate not only the attitude parameter but also the gyro drift.The determination accuracy of the attitude estimator can meet the attitude determination requirements of the most spacecrafts.