地月平动点导航星座的概要设计与性能分析

Outline design and performance analysis of navigation constellation near earth-moon libration point

研究应用地月平动点轨道的深空导航星座的概要设计问题.首先,建立三体平动点动力学模型,给出计算平动点周期轨道族的微分校正算法,并介绍周期轨道的稳定性因子概念;然后,定义有效覆盖概念,分析实现有效覆盖的平动点导航星座的相关要素,给出设计步骤;在此基础上,分别从轨道选择、空间覆盖率、几何精度衰减因子、导航信号传输、导航精度等角度,对平动点导航星座进行设计、分析与估算,以全球定位系统为参照,通过综合对比分析,全面论证平动点导航星座的可行性,并给出技术指标与性能.研究表明:采用所设计的地月L3平动点Vertical轨道的5星星座可为地月空间各种飞行器提供有效覆盖的导航服务,在不考虑星座卫星等误差因素情况下,导航精度可优于10 m,并可随导航卫星数目增加而进一步提高.

The outline design problem of navigation constellation near libration point is studied for deep space exploration. Firstly, the model of circular restricted three body problem near libration point is given, and the differential correction method is provided to calculate periodic orbits, of which the stability factor is also introduced. Secondly, the concept of effective coverage is defined, and the elements and the steps to design the constellation are proposed. Then, the outline design, performance analysis and evaluation of the navigation constellation are carried out concretely from aspects of orbits selection, space coverage, geometric dilution of precision factor, signal transmission and navigation precision. Compared with the case of global position system, the feasibility of the navigation constellation in libration point orbit is proved, and the performance index is provided. By analysis, the designed navigation constellation in L3-Vertical orbit with 5 satellites is able to provide navigation service for most of the spacecrafts in the space of between the earth and the moon, and the navigation precision is better than 10 m if the orbit determination errors of the constellation are not considered.