Mega-constellation coverage performance analysis based on improved visibility function under multiprecision grid point method

Coverage performance is an important index to evaluate the reliability and stability of the service provided by the megaconstellation. Different from traditional constellations, mega-constellation has a large number of satellites distributed in several different orbital planes, which leads to a sharp increase in the calculation amount of traditional coverage performance analysis methods. In this paper, the position of the satellite is deduced by TLE (Two-Line Elements) data and SGP4 (Simplified General Perturbations Satellite Orbit Model 4) model. Then, a multi-precision method for dividing grid points is proposed, which is different from the traditional method of dividing grid points at equal intervals. The longitude interval is set according to the latitude in the method, so as to avoid the excessive division of longitude in the high latitude region. Meanwhile, the selection of grid points near the 180° longitude line is optimized in view of the characteristics of the coincidence of the 180° east-west longitude line. On this basis, an improved visibility function model is constructed which comprehensively considers the beamwidth of satellite antenna and the minimum elevation angle of grid point to analyze the coverage performance of mega-constellation, overcoming the problem that the traditional visibility function model cannot consider the restriction of the beamwidth of satellite antenna to the coverage performance. Finally, this paper takes OneWeb constellation as an example to analyze the proposed method, and compares it with the traditional method. The simulation results show that the proposed method can greatly reduce the computational complexity while ensuring the accuracy of the calculation results.