Performance evaluation of a lunar navigation system exploiting four satellites in ELFO orbits

ESA and NASA are proposing satellite based lunar communication and navigation systems deployed in Moon orbit; in this way, lunar vehicles/spacecraft will be able to accomplish more complicated missions and to operate with minimal control from the Earth. Different solutions have been proposed in the literature, but no final decision has been taken so far.In this work, it is evaluated a possible solution that exploits a small number of satellites deployed in ELFO orbits.Starting from the classical definition of Dilution Of Precision used for the One-Way localization in GNSS systems and the User Equivalent Range Error definition, the peculiarities of the Moon scenario are considered and used to derive the expected level of accuracy and availability obtainable on the south hemisphere of the Moon. Results show that good performances can be obtained at the low latitude of the Moon, and in particular at the South Pole.