利用X射线脉冲星和多普勒频移的组合导航

Integrated X-ray Pulsar and Doppler Shift Navigation

为了提高航天器自主导航能力,提出了一种利用X射线脉冲星和多普勒频移的组合导航方法。多普勒导航利用相对于太阳的多普勒径向速度作为量测信息,该方法不能得到所有的状态估计。脉冲星导航系统具有完全可观测性,但是滤波周期较长,不能提供连续的导航信息。因这两种方法具有互补性,利用联邦滤波器来融合脉冲星导航与多普勒导航提供的信息。由于两种方法的量测方程与状态方程都是非线性的,采用无迹卡尔曼滤波器(UKF)作为子滤波器。实验结果验证了该导航方法的可行性和精确性。与脉冲星导航方法相比,该组合导航方法可提供更高的位置估计精度。

In order to improve the autonomous navigation capability of spacecraft,an integrated navigation method using X-ray pulsar and Doppler is proposed.The Doppler navigation takes the Doppler radial velocity relative to Sun as measurement information,and this method can not obtain all state estimates.The pulsar navigation system is completely observable,but the filtering period is too long to provide continuous navigation information.Because the two methods are complementary to each other,a federated filter is utilized to fuse the information from the pulsar navigation and the Doppler navigation.Because both the state equation and the measurement equation of two methods are nonlinear,an UKF （Unscented Kalman Filter） is used as a local filter.The simulation results have demonstrated feasibility and accuracy of this navigation method.Compared with the pulsar navigation,the integrated navigation method can provide higher position estimation accuracy.