Augmentation is a way for integrity improvement of GNSS systems. SBAS systems use GEO satellites for augmentation. EGNOS includes GNSS systems, three GEO satellites for sending corrections to all possible GNSS users in Europe, ground segment and user segment. The most valuable aspect is the possibility for the user to compute a protection level PL that over bounds the navigation system error experienced by the user with the integrity risk requirement. EGNOS is certified for safety of live (SoL) services. This is a very important step forward for the global and especially European aviation.
