To maintain the safety by avoiding deterioration in the positioning accuracy through making SBAS satellite navigation data used in a ground system and in an airborne system consistent by employing GBAS. The system includes: a ground system which estimates errors contained in ranging signals received from the navigation satellites, and formats and transmits correction information for correcting the estimated errors; and an airborne system which calculates differential GPS positioning based on the ranging signals received from the navigation satellites and the formatted correction information, and displays a displacement from a regulated route. The ground system notifies update, when SBAS satellite navigation data used for generating the correction information is updated, by adding information regarding update of navigation data to the correction information. The airborne system detects the transmitted update notification of the SBAS satellite navigation data, and calculates the differential GPS positioning by switching to the updated navigation data.