LEO constellation optimization for LEO enhanced global navigation satellite system (LeGNSS)

Low Earth Orbit (LEO) enhanced Global Navigation Satellite System (LeGNSS) has been recognized as the promising positioning system in the near future where mega-constellations of LEO satellites are used for precise positioning. Fast Precise Point Positioning (PPP) convergence can be achieved if LEO constellations are employed into current GNSS due to the fast motion of LEO satellites. In order to fulfill this purpose, it is of great importance to design a LEO constellation or to conduct LEO constellation optimization for global precise positioning. In this article, several aspects of LEO constellations in terms of number of LEO orbital planes, number of LEO satellites, and the selection of orbital inclinations are statistically analyzed to find out the suitable LEO constellation for LeGNSS. It is shown that the combination of several LEO constellations with different inclinations together as a whole would be much more appropriate to get a more uniform distribution of the number of visible LEO satellites along the latitude for global fast convergent PPP. With a total 240 LEO satellites of orbital inclinations at 90°, 60°, and 35° selected in this article, one minute convergence time for PPP is achieved on a global scale.