一种基于天文测速的火星捕获段天地联合导航方法

为提高火星捕获段探测器的导航精度，提出一种基于天文测速的天地联合导航方法。该方法在地面无线电测距、测速的基础上，引入探测器与恒星的视向速度作为新增观测量，采用扩展卡尔曼滤波(EKF)对探测器状态进行估计。理论分析与仿真结果均表明，与仅依靠地面无线电导航相比，采用基于天文测速的天地联合观测导航方法能有效提高探测器的位置与速度估计精度，且导航精度的提升效果与马尔柯夫最优估计理论的预测值有较好的吻合度。当天文测速精度与地面测速精度相当时，位置估计精度较地面无线电导航提高了近一倍。

A Space Ground Combined Navigation Method Based on Celestial Velocity Measurement for Mars Capture Phase

To improve the navigation accuracy for the Mars capture phase, a space-ground combined navigation method based on celestial velocity measurement is proposed in this paper. The radial velocity between the probe and the star is introduced as a new observation in addition to the ground radio ranging and velocity measurements. The Extended Kalman Filter (EKF) is applied to estimate the state of the probe. Both theoretical analysis and simulation results show that compared with traditional ground-based radio navigation, the position and velocity estimation accuracy in the Mars capture phase can be improved effectively when the proposed method is utilized. Furthermore, the accuracy improvement conforms to the prediction of the Markov optimal estimation theory. When celestial velocity measurement noise and ground velocity measurement noise are on the same level, the position estimation accuracy will be two times better.