Assessment of Different Dual-frequency Dual-constellation GBAS Processing Modes based on Flight Trials

Kurzfassung

In this paper we present the expected performance of different processing modes for a future dual-constellation dual-frequency Ground Based Augmentation System (GBAS). The evaluations are based on measurements collected during flight trials. We discuss the changes to the residual differential error for each processing mode. In our previous work we derived preliminary airborne multipath (σair) and ground multipath (σgnd) curves for Galileo E1 and E5a signals and GPS L5 signals. We use these models in our evaluations. After discussing the benefits of adding a second constellation in the GBAS implementation we will focus on the modes enabled by the addition of a second frequency, mainly the single frequency L5/E5a mode and the Ifree mode. We compare the errors and the nominal protection levels of the new processing modes with the current GAST-C and GAST-D. This work contributes to the analysis and trade-off considerations in the development of a future DFDC GBAS standard.