GEO SATELLITE AUTONOMOUS NAVIGATION USING X-RAY PULSAR NAVIGATION AND GNSS MEASUREMENTS

Autonomous navigation for High Earth Orbits satellites such as GEO is challenged due to the limitation of the uses of the existing onboard navigation solutions such as GPS/GNSS, celestial navigation. XNAV Navigation for spaceships using X-ray pulsars shows potential to be the ultimate natural UPS system as an interstellar navigation tool. It indicates that XNAV could assist these to overcome this challenge, an algorithm for satellite autonomous navigation using X-ray navigation and GNSS is presented. X-ray Navigation also known as XNAV is a novel celestial navigation method for aerospace vehicle time, position and attitude determination. X-ray navigation is a GPS-like location technique. GPS/GNSS is demonstrated as an efficient navigation method for GEO. This method utilized an onboard GPS/GNSS receiver to determine the position. The state-of-the-art shows the onboard multi-GNSS will be most likely to be utilized in the earliest real autonomous navigation application. The algorithm is based on a federal Kalman filter and processes X-ray phase measurements and GNSS pseudo-range. Simulation indicates that the integration of X-ray navigation and GNSS achieves position and velocity accuracy better than the performance of single system. Accordingly, the reliability of the entire navigation system can be enhanced through the integration that renders the system especially attractive for future highly autonomous satellite missions.