The document discusses the concept and development of a potential Lunar Orbiting Navigation (LON PNT) system, which aims to augment existing Global Positioning System (GNSS) constellations with additional navigation signals from Lunar Orbit (LEO), while still relying on the GPS for orbit determination and time synchronization.

The system will be tested in the ATOMIC mission, expected to launch in 2024, which will demonstrate Orbit Determination and Time Synchronization (ODTS) in orbit.

The document also mentions the evaluation of different real-time ephemerus generation algorithms based on real on-board data as a next step in the design of a fully operational LON PNT payload.