A Novel Navigation Message for LEO Satellites

There is a growing interest in the use of low Earth orbit (LEO) satellites for providing position, navigation and timing (PNT) services and several initiatives are being launched in different parts of the world aiming to explore this concept. LEOs have some distinctive characteristics with respect to medium Earth orbits (MEO) currently used by global navigation satellite systems (GNSS) including lower signal propagation losses, faster geometry changes and lower latencies. As part of Future NAV LEOPNT project, the European Space Agency (ESA) will develop and deploy an in-orbit demonstrator (IOD) for LEO PNT. In the context of this initiative, PNT signals will be broadcast by LEO satellites. These signals will include navigation messages which will include clock and ephemeris data as this is essential to provide PNT services.