编队卫星相对位置测量信息自主确定月球引力场的方法

针对月球远月面引力场的数据不能直接测量而导致其测量精度不高的问题,提出了一种基于双星编队的月球引力场自主确定方法。该方法考虑到月球引力场对编队卫星相对运动的影响,通过扩展卡尔曼滤波算法对星间距离测量数据的处理,利用观测量的测量值与一步预测测量值之间的偏差来修正一步预测状态值,从而得到状态估计量,即实现了卫星自主定轨以及月球引力场的自主确定。仿真结果表明,根据对编队卫星在7 430s内的相对位置测量数据的处理,卫星轨道位置和速度确定精度分别能达到5.04m和6.07×10~(-3) m/s;月球J2项摄动常数的精度能达到9.14×10~(-8) ;月球引力场常数的精度能达到3.47×10~7 m~3/s~2。此结果能在一定程度上改善现有的月球引力场模型,为我国"嫦娥工程"提供更多的技术资料。

Autonomous lunar gravitational field determination via relative position measurement of the satellite formation

In view of the shortcoming that the data of the lunar back, cannot be directly measured and it leads to the low accuracy of the gravitational field, we propose an autonomous lunar gravitational field determination method based on dual satellite formation. Considering the effect of the lunar gravitational field on the relative position of satellite formation, the proposal adopts the extend Kalman filter (EKF) algorithm to handle the measurement data of satellite distance, and uses the difference between the measured data and the predicted data to modify the predicted status so as to obtain the estimate value of the status, thus realizing autonomous precise orbit determinations and determining the lunar gravitational field. The resulting system can achieve an orbital position accuracy of 5.04 m, an orbital velocity accuracy of 6.07×10-3 m/s, a gravity accuracy of 3.47×107 m3/s2 and the coefficient of a lunar perturbation accuracy of 9.14×10-8 in the time period of approximately 7 430 seconds. Simulation results verify the effectiveness of the program and improve the existing model of the lunar gravitational field to a certain extent. It can provide more technical information for the “Chang E Project” of China.