立方星剩磁在轨辨识与主动补偿技术

立方星的姿态测量与控制系统常采用磁测磁控结合偏置动量轮的方案,整星剩磁干扰力矩是影响姿态控制精度的重要因素之一。提出了一种利用磁强计实现剩磁矩在轨辨识与利用磁力矩器实现剩磁矩主动补偿的新方案:基于磁强计输出和卫星姿态动力学建立了剩磁矩在轨辨识模型,并利用采样滤波器(UKF)提高单磁强计条件下的辨识效果;把控制对象简化成线性定常系统,分析了剩磁干扰力矩对姿态的影响数学模型,并针对磁力矩器和磁强计分时工作的特点,基于叠加性原理提出了基于角速度的剩磁矩主动补偿算法。仿真研究表明,在1000 s内剩磁矩在轨辨识精度为0.001 A×m~2量级,主动补偿后,偏航角、滚动角与俯仰角控制误差分别从4.3°、4.6°与2.1°均减少至0.4°以内。提出的方法为类似配置卫星减少剩磁干扰力矩的影响提供了一种新思路。

On-orbit estimation and compensation for CubeSats remanence

A CubeSat usually utilizes magnetometer, magnetorquer and momentum wheel to determination and control its attitude, and the remanence disturbance torque is one of factors that influence the performance of the attitude determination and control system. A new method for realizing the remanence’s on-orbit estimation and compensation is proposed which only utilizes data from the magnetometer and the magnetorquer. First, a remanence on-orbit estimation model is derived by employing the magnetometer outputs and satellite attitude dynamics, and an unscented Kalman filter is utilized to improve the estimation with a single magnetometer. Second, after simplifying the system into a linear time-invariant system, the remanence disturbance which affects the satellite attitude is mathematically modeled according to the superposition principle, and then a remanence compensation method with the criterion of removing angular velocity disturbance is presented in consideration of time-sharing between magnetometer and magnetorquer. Finally, simulations are made which show that the remanence’s estimation accuracy is better than 0.001A?m2 in 1000s, and the heading, roll and pitch angles are reduced from 4.3°, 4.6° and 2.1° respectively to within 0.4°. The proposed method is a new way to reduce the remanence disturbance for satellites.