Flight Testing the GAST D Solution at DLR's GBAS Test Bed

Abstract

In 2011 we performed a series of flight trials for evalua-tion of the CAT-III GBAS system and testing its capabili-ties in an operational environment. In the first campaign we flew a total of 17 approaches on two days at the end of August 2011 and two days at the beginning of November with DLR’s VFW-614 research aircraft. In December we continued the trials with our Airbus 320 as a representative commercial aircraft for today’s air traffic. To evaluate performance of the GBAS based navigation we post processed a dual frequency carrier phase trajectory in a combined forward and backward solution as a truth reference. We will present the relevant parameters from all flights, putting special emphasis on the GAST D specific aspects. These mainly include the outputs of the ionospheric monitoring schemes and geometry screening aspects. As the flights were performed on days without ionospheric disturbances we had no detections of monitors throughout the flight. At all times the performance was well within all limits and vertical accuracy typically better than 1m. Furthermore, we compared the calculated deviations to the measured ILS deviations during the flight and saw significantly less noise on the GBAS guidance signals.