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地磁场矢量可描述成卫星的位置函数,利用三轴磁强计观测地磁场矢量或模,可实现近地卫星在任何运行状态下的自主导航,但是由于地球磁场模型存在不确定性和长期变化性,三轴磁强计存在安装误差和未知比例因子等误差因素,所以目前单一使用三轴磁强计进行自主导航精度有限。提出一种利用地磁场信息在轨修正地磁场模型高斯系数和标定三轴磁强计模型误差的新方法,通过将三轴磁强计与地磁场模型参考值的矢量和模分别作差,推导两种差值与地磁场模型高斯系数和三轴磁强计模型误差参数的数学关系,设计先进滤波算法得到高斯系数及误差参数的最优估计,实时修正地磁场模型和三轴磁强计模型。以某低轨卫星利用地磁场进行自主导航为例,利用数值仿真验证在轨修正后地磁场模型和标定后三轴磁强计模型,并对3种自主导航方法进行仿真结果的分析和比较,论证所设计方法既提高系统导航精度、收敛性和稳定性,又有利于工程实际应用。
The geomagnetic vector can be described as a satellite’s position function. Using the three-axis magnetometer to observe the geomagnetic vector or mode, it can realize the autonomous navigation of the near-earth satellite under any operating condition. However, due to the uncertainties and long-term changes of the earth’s magnetic field model The three-axis magnetometer has some error factors such as installation error and unknown scale factor, so the accuracy of autonomous navigation using a single three-axis magnetometer at present is limited. A new method to correct the Gaussian coefficient of geomagnetic field model and calibrate the model error of three-axis magnetometer using on-orbit information of geomagnetic field is proposed. The difference between the vector and the modal of the geomagnetic field model reference value Two kinds of difference and the geomagnetic model Gaussian coefficient and three-axis magnetometer model error parameters of the mathematical relationship between the design of advanced filtering algorithm Gaussian coefficient and error parameters to obtain the best estimates of real-time correction of geomagnetic field model and three-axis magnetometer model . Taking a low earth orbit satellite as an example, autonomous navigation using geomagnetic field is taken as an example. The modified geomagnetic field model after calibration and the calibrated three-axis magnetometer model are validated by numerical simulation, and the simulation results of three kinds of autonomous navigation methods are analyzed and compared. The proof design method not only improves the precision, convergence and stability of the system navigation, but also is beneficial to the practical application of the project.