基于Lawden改进型方程的编队Unscented Kalman Filter滤波估计

The Unscented Kalman Filter Estimation of Spacecraft Formation Flying Based on Improved Lawden Equation

通过改进卫星编队的Lawden方程得到非线性相对运动方程,称为Lawden改进型方程,使其更加近似于编队运行环境。通过该非线性方程,在编队相对导航研究中,以EKF滤波方法为参考分析,采用适合非线性系统的UKF(Unscented Kalman Filter)滤波方法对编队的状态进行滤波估计。通过仿真实验,结果表明采用UKF滤波方法的编队状态估计精度明显优于采用EKF滤波方法得到的估计精度,其中相对距离估计精度可以提高70%左右,相对速率估计精度可以提高25%左右,在工程应用中具有一定的参考利用价值。

The improved Lawden equation based on the Lawden equation of spacecraft formation flying is obtained. Through the new equation, the formation flying state can be estimated by using unscented Kalman filter. The result of stimulation shows that the more accurate state estimation can be obtained by using UKF than that of EKF. Comparing to EKF, about 70% higher accuracy on formation relative position estimation and 25 % higher accuracy on formation relative speed estimation can be obtained by using UKF. It indicates that it has well efficiency in the practical application based on the improved Lawden equation by using UKF.