The GPS (Global Positioning System) is widely used as a precision positioning sensor, and contributes effectively to the PBN (Performance Based Navigation) in the aeronautical navigation. On the other hand, in cases that many airplanes experience GPS-OUT simultaneously, the ATC (Air Traffic Control) may not timely be aware of the situation. Thus, the realization of GNSS (Global Navigation Satellite System) monitoring on the ground is essential to achieve the safe operation with expanded capability expected to the PBN. The authors have assessed the idea of the real-time ground monitoring for onboard ABAS (Aircraft-Based Augmentation System) performance with demonstration of short-time performance predictions of some airplanes in operation. This paper reports on the validity of the ground monitoring for onboard ABAS performance, using the ADS-B (Automatic Dependent Surveillance-Broadcast) downlink messages in flights around Tokyo.

Keywords: GPS, ABAS, RAIM, PBN, GNSS, performance monitoring