Lunar Surface Navigation System

Scientists at NASA’s Langley Research Center have developed a novel concept for a lunar navigation system based on the reverse-ephemeris technique. Typically, range-related signal measurements from the Earth’s surface are used to locate and track orbital objects (satellites) and establish the ephemeris describing their orbits. For this reverse-ephemeris lunar navigation concept, the process is reversed to give lunar surface position fixes using the known ephemeris of a satellite in lunar orbit.