Abstract: 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.

Key words: constellation design, elasticity, regional coverage, multi-satellite launch, multi-level region