Lunar Global Positioning System using L₁ and L₂ libration points

Abstract

This paper deals with the realization of a Lunar Global Positioning System that uses two constellations of satellites around the collinear L1 and L2 libration points of the Earth - Moon system. Analytical solutions for periodic orbits around the collinear points have been investigated in the frame of the restricted three and four body problem. Different kinds of periodic orbits and geometry configurations for the constellations have been studied in order to minimize the amount of Δv needed for the station keeping maneuvers, also taking into consideration the requirements of satellites' visibility from the Earth and coverage of the lunar surface. Particular attention was given to the definition of geometries of the constellations that guarantee coverage of the polar regions, due to their great importance in the renewed interest for lunar exploration. A short description of the control technique used for the station keeping is provided as well.