High precision attitude determination algorithm based on observations of the sun guide telescope
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).
observing the Sun activityattitude determinationSun guide telescope(SGT)extended Kalman filer(EKF)
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