Fully-Connected LEO Hybrid Constellation Design with Global Uniform Coverage

Low Earth orbit mega-constellations have been deployed with the development of small satellite technology, and the decrease in satellite manufacturing and launch costs. The network connectivity and coverage performance are important factors in evaluating the low Earth orbit mega-constellation system. This study considers the problem of designing a low Earth orbit hybrid mega-constellation to achieve global uniform coverage considering the constraint of constellation connectivity. First, the precondition of establishing inter-satellite links is analyzed and characterized by inter-satellite angular distance. The constraint of the satellite phase and the topology design method among sub-constellations are derived. Then, the coverage longitude width model is established and the coverage ratio of latitudes is proposed. Finally, the coverage uniformity and connectivity models are proposed as the objective and constraint respectively in the hybrid constellation optimization model. A hybrid constellation design example is provided, which achieves a uniformity metric of 0.0186 and a maximum transmission hop of 6.