Precise real‐time navigation of LEO satellites using GNSS broadcast ephemerides

Abstract The availability of orbit information with high precision and low latency is a key requirement for many Earth-observation missions, predominantly in the field radio occultation. Traditionally, precise determination solutions low-Earth (LEO) satellites are obtained offline on ground after downloading GNSS measurements auxiliary spacecraft data to processing center. this depends frequency LEO downlink contacts clock products required process. These dependencies can be removed by computing solution board satellite using broadcast ephemerides. In study, both real simulated from representative processed flight-proven Kalman-filter algorithm. paper studies use GPS, Galileo BeiDou-3 real-time different combinations measurements. Results show that dual-frequency observations ephemerides leads significant reduction 3D rms errors compared GPS-only processing. An onboard navigation accuracy about one decimeter achieved without external augmentation data, which opens up new prospects conducting relevant parts science future space missions directly satellite.