GBAS/INS Navigation System: Further Developments of On-Board Integrity Monitoring

摘要

At present, Ground Based Augmentation Systems (GBAS) CAT-I operations are almost certified. The principle is published in DO245A [1] where it is outlined that the GBAS ground station must assure the integrity within the service volume. But recent investigations (see [2] and [3]) have shown that for certain circumstances (e.g. ionospheric local disturbances) the integrity cannot be guaranteed for approaches equivalent to ILS CAT-II and CAT-III operations. This is one reason why new system approaches are currently under discussion on international level. One way to reach highest aircraft performance levels is to implement independent monitors on ground and also on-board the aircraft. The system described in this paper uses Inertial Measurement Units (IMU) to augment the GBAS corrected ranging sources on user level (i.e. aircraft level). While the basic system was already presented in [4], this paper focuses on the integrity monitoring functions of the system. Results are shown and compared to the sole GBAS solution for different flight trials.