基于太阳导行镜测量的高精度姿态确定算法

High precision attitude determination algorithm based on observations of the sun guide telescope

先进天基太阳天文台卫星(advanced space-based solar observatory satellite,ASO-S)的主要任务是对日观测,对卫星姿态确定精度提出了较高的要求。为此,提出了一种新的姿态确定算法使用ASO-S科学载荷太阳导行镜(Sun guide telescope,SGT)测量卫星指向与太阳中心的偏差角,以及对光纤陀螺(fiber optic gyro,FOG)和星敏感器(star trackor,STR)测量值进行姿态确定。将卫星本体系姿态四元数矢部和FOG常值零位漂移作为状态变量,STR和SGT观测值作为测量变量,设计扩展卡尔曼滤波器(extended Kalman filter,EKF)。通过数学仿真验证本文所设计姿态确定算法的正确性与稳定性。最后,利用ASO-S在轨遥测数据进行验证,基于SGT测量的姿态确定算法可显著提高卫星非对日方向的姿态角估计精度,可优于0.2″(3σ)。

The main task of the advanced space-based solar observatory satellite(ASO-S)is observing the Sun activity.There is a particular request for high-precision attitude determination.A new attitude determination algorithm is proposed to achieve this task.The Sun guide telescope(SGT),which is one of the scientific payloads onboard ASO-S,can measure the deviation angles between satellite’s pointing direction and center of the sun.So the measurement values of SGT and those from fiber optic gyro(FOG)and star tracker(STR)are used for attitude determination.The vector part of attitude quaternion in body coordinate system and the constant zero drift of FOG constitute the state variables.The measurable variables are composed of measurements from STR and SGT.They are both used to design an extended Kalman filer(EKF).A mathematical simulation is used to validate the correctness and stability of the proposed algorithm.Finally,on-orbit telemetry data of ASO-S is used to verify the present approach.The attitude determination method based on observations of SGT can obviously improve the estimation accuracy of attitude angle in the non-sun pointing direction,which can be less than 0.2″(3σ).