多等级区域侦察弹性星座设计方法

针对传统侦察星座目标单一、弹性低的问题，提出了多等级区域侦察弹性星座的设计方法。该方法将星座设计过程按区域等级信息分为多个子星座逐步设计，直到整体星座对所有的区域性能满足设计要求。以区域被划分为3个等级为例，首先对星座设计需求、设计指标及设计步骤进行了分析。其次推导了地面最低分辨率和轨道高度的关系并确定了不同子星座的轨道高度。最后考虑轨道倾角、一箭多星发射、光照和升交点漂移同步约束，构建基础星座、子星座1和子星座2的优化模型。最终设计星座为3层混合星座，共8个轨道面和70颗卫星，星座对各等级区域的最大重访时间分别为10937s，12241s和17437s，弹性指数为2213%，2420%和6361%。结果表明该方法设计的星座可实现对区域覆盖和弹性分级的设计要求，证明了方法的有效性。对比Walker星座设计方法，在同等设计要求下，Walker星座所需卫星数为156颗，多等级区域侦察弹性星座所需卫星数远低于Walker星座，结果进一步证明了该星座设计方法的优越性。

Design method of multi-level regional reconnaissance elastic constellation

A design method of multi-level regional reconnaissance elastic constellations was proposed. The constellation design process was divided into three sub-constellation design steps according to region information until the whole constellation met the design requirements for all regional performance. Taking regions divided into 3 levels as an example, the constellation design requirements, design indicators and design steps were analyzed firstly. Then the relationship between the minimum resolution of the ground and orbital altitude was derived and the orbital altitude of different sub constellations was determined. Finally, the optimization models of basic constellation, sub constellation 1 and sub constellation 2 were constructed by considering orbital inclination, multi satellite launch and ascending nodal drift synchronization. The design case shows that the constellation designed with this method can meet the design requirements of regional coverage classification and elastic classification, which proves the effectiveness of the method. Compared with the design method of Walker constellation, the number of satellites required for multi-grade regional reconnaissance elastic constellation under the same design requirements is far lower than that of Walker constellation, which further proves the superiority of the proposed design method.