大不确定性条件下火星进入高精度组合导航方法研究

发布时间：2018-06-05 22:50

本文选题：火星进入 + 大不确定性　；参考：《南京航空航天大学》2015年硕士论文

【摘要】：火星进入动力学过程存在着大气密度不确定性及其引起的飞行器气动参数的不确定性偏差,成为阻碍火星着陆精度进一步提升的“瓶颈”。火星进入段导航与制导精度是决定最终着陆精度的最主要因素,但以往的基于惯性航位推算的进入导航方式不能满足未来火星精确着陆任务要求,亟需开发考虑大不确定性因素的火星进入导航新技术。本学位论文从组合导航方案、导航滤波算法、可观性分析三个方面出发,对大不确定性条件下火星进入高精度组合导航方法进行了研究。首先,基于给定的火星环境模型和进入器构型,分别建立了用于模拟真实飞行状态的仿真动力学模型和用以进行滤波器设计的演化动力学模型。然后,利用三个轨道器与进入器的无线电测量作为外部修正,发展了基于不敏感扩展卡尔曼滤波的火星进入组合导航算法;仿真结果表明,该算法能够抑制不确定性偏差对导航滤波的不利影响,从而获得较高的导航精度。接着,利用一个轨道器加两个火星表面信标与进入器的无线电测量作为外部修正,设计了基于修改多模型自适应估计的火星进入组合导航算法;仿真结果表明,该算法增强了对不确定性参数的适应性,在进一步提高导航精度的同时,也实现了对火星大气密度的准确估计。最后,对上述两个火星进入组合导航算法进行了定性和定量的可观性分析;结果表明,外部测量几何关系是决定可观测度和导航误差的主要因素,而动力学模型的不确定性偏差会在局部范围内影响可观测度和导航精度。
[Abstract]:The uncertainty of atmospheric density and the uncertainty of aerodynamics parameters caused by the uncertainty of atmospheric density in the dynamic process of Mars entry have become the "bottleneck" which hinders the further improvement of Mars landing precision. The navigation and guidance accuracy of Mars entry section is the most important factor to determine the final landing accuracy, but the previous navigation mode based on inertial reckoning can not meet the requirements of future Mars precise landing mission. There is an urgent need to develop new Martian navigation technologies that take into account great uncertainties. Based on three aspects of integrated navigation scheme, navigation filtering algorithm and observability analysis, this thesis studies the method of Mars entering into high precision integrated navigation under the condition of great uncertainty. Firstly, based on the given Mars environment model and the entrant configuration, the simulation dynamics model for simulating the real flight state and the evolutionary dynamics model for filter design are established, respectively. Then, using radio measurements of three orbiters and entrants as external corrections, an insensitive extended Kalman filter (EKF) based integrated navigation algorithm for Mars entry is developed. The simulation results show that, The algorithm can suppress the unfavorable influence of uncertainty deviation on navigation filtering and obtain high navigation accuracy. Then, a Mars entry integrated navigation algorithm based on modified multi-model adaptive estimation is designed using a single orbiter plus two mars surface beacons and radio measurements of the entrant as external corrections. The simulation results show that, The algorithm improves the adaptability of uncertain parameters and improves the accuracy of navigation. At the same time, it also realizes the accurate estimation of the atmospheric density of Mars. Finally, the qualitative and quantitative observability analysis of the two mars entry integrated navigation algorithms is carried out, and the results show that the external measurement geometry is the main factor that determines the observability measure and navigation error. The uncertainty deviation of dynamic model will affect observable measure and navigation accuracy in local range.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：V448.2

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