基于脉冲星和火星观测的深空探测器自主导航

Autonomous navigation for deep space explorer based on pulsar and Mars observation

为了消除脉冲星星历误差并提高火星探测巡航段末端导航精度,提出了一种基于脉冲星和火星观测的组合导航方法。受当前测量技术的限制,脉冲星星历信息中不可避免地存在误差,此时,X射线脉冲星导航定位精度较低。现有的火星敏感器精度较低,此外,基于火星观测的自主导航方法定位精度与火星和深空探测器之间的距离有关。即使在巡航段末端,基于火星观测的自主导航方式精度仍有限,不能满足火星探测需求。鉴于二者的互补性以及导航系统的非线性,将脉冲星星历误差引起的系统偏差作为增广状态,利用扩展Kalman滤波器将二者的导航信息融合。与脉冲星导航和基于火星观测的自主导航方法相比,该组合导航方式对脉冲星星历误差和火星敏感器误差具有较强的鲁棒性,且定位精度较高,能满足火星探测的需求。

In order to eliminate the pulsar ephemeris error and improve the navigation accuracy at the cruise phase tail end of Mars explorer, an integrated navigation method based on pulsar and Mars observation is proposed. Subject to the limitation of current measurement technology, there is an unavoidable error in the pulsar ephemeris informa- tion. Under this condition, the positioning accuracy of X-ray pulsar navigation is very low. Subject to the low accura- cy of Mars sensor and the long distance between the Mars and the deep space explorer, the Mars observation-based navigation method ,whose accuracy at the cruise phase tail end is low, does not satisfy the requirement of Mars explo- ration. As the two methods are complementary to each other, and the navigation system is nonlinear, the system bias caused by the pulsar ephemeris error is considered as the augment state, an extended Kalman filter is adopted to fuse their navigation information. Compared with the pulsar navigation and the Mars observation-based navigation, this in- tegrated method is robust to the pulsar ephemeris error and the Mars sensor error, and its positioning accuracy is high, which can meet the requirement of the Mars exploration.