Multi-orbit Lunar GNSS Constellation Design with Distant Retrograde Orbit and Halo Orbit Combination

The Moon is the closest natural planet to mankind, with valuable resources on it, and is an important base station for mankind to enter deep space. How to establish a reasonable lunar Global Navigation Satellite System (GNSS) to provide real-time positioning, navigation, and timing (PNT) services for moon exploration and development has become a hot spot for many international scholars. Based on the special spatial configuration characteristics of Libration point orbits (LPOs), the coverage capability of Halo orbits and Distant Retrograde Orbit (DRO) in LPOs is discussed and analyzed in detail. It is concluded that the Halo orbit with a period of 8 days has a better coverage effect on the lunar polar regions and the DRO has a more stable coverage effect on the lunar equatorial regions, and the multi-orbital lunar GNSS constellation with the optimized combination of DRO and Halo orbits is proposed by combining the advantages of both. This multi-orbital constellation can make up for the fact that a single type of orbit requires a larger number of satellites to fully cover the Moon, using a smaller number of satellites for the purpose of providing PNT services to the entire lunar surface. The design of the multi-orbital lunar GNSS constellation meeting the requirements of real-time positioning on the whole moon surface in two sets is given in combination with simulation calculations. The simulation experiment results show that the multi-orbital lunar GNSS constellation n combining DRO and Halo orbit can cover 100% of the moon surface, and there are more than 4 visible satellites at any time on the moon surface, which meets the navigation and positioning requirements, and the PDOP value is stable within 2.0, which can meet the demand for higher precision moon surface navigation and positioning.