Optimization Design of Global Low-orbit Satellite Constellation for Multi-fold Coverage

In recent years, the low-orbit satellites constellation has developed rapidly at home and abroad, involving navigation, remote sensing, communications, the internet and other fields. The performance of constellations will be influenced by multi-fold coverage heavily. For instance, the location of the radiation source is determined by multi-fold coverage at Hawkeye 360. The ability to track missiles was improved by multi-fold coverage at SBIRS-LEO. Not only that, the fold coverage of small satellite constellation is particularly important in the early stage of the demonstration. The objective of this paper is to propose an optimization method based on multiple coverage constellations. There are more scholars studying continuous global coverage constellation, but few scholars study multi-fold coverage. This article proposes the two-fold coverage width function near equator, and proposes a constellation optimization design process considering the height of orbit and the number of satellites. Then initial parameters will be obtained from the single continue global coverage satellite constellation designed by SOC method. The constellation will be optimized by the method proposed in this paper. Finally, the parameters of the constellation will be obtained and performance of the digital transmission opportunities is excellent. The designed constellation satisfies the demand of multi-fold coverage and has certain reference significance for small satellite constellation design.