Extended 2-D Map for Satellite Coverage Analysis Considering Elevation-Angle Constraint
Yi Gu, Yuhan Chen, Yujin Zhang, Guohua Wu, Shengzhou Bai
Abstract
The analysis of satellite coverage to determine the visibility of ground targets from satellites has been extensively studied, particularly through geometric-based methods that provide analytical results. However, there exists a key limitation that these methods do not precisely consider the elevation-angle constraint. To address this limitation, this article provides a geometric approach for computing the visibility considering the elevation-angle constraint. First, the mathematical model of the elevation-angle constraint is established, and the elevation-element equation describing the geometrical relationship between satellite and ground target satisfying the elevation-angle constraint is deduced. Additionally, based on the analytical solution to the elevation-element equation, a two-dimensional map, named the elevation mapping, is proposed. Subsequently, the presented geometric approach is established by incorporating the elevation-angle constraint model into the satellite-target visibility model, and an extended field mapping is proposed to rapidly compute access intervals while adhering to the elevation-angle constraint. Specifically, it achieves this by converting the task into a straightforward problem involving the intersection of a set of lines with the time-invariant regions generated by the extended field mapping. Furthermore, the extended constellation field mapping is presented, which can simplify the multisatellite coverage problem into an easier single-satellite coverage problem, enabling it to solve the constellation coverage problem considering elevation-angle constraints analytically and rapidly. Simulation results demonstrate that the proposed intuitive methodology can accurately and rapidly compute access intervals while considering the elevation-angle constraint, which suggests its wide applications in satellite coverage analysis.