Ionosphere Threat Space Model Assessment for GBAS

C. Mayer, B. Belabbas, N. Jakowski, M. Meurer, W. Dunkel

Abstract:	Ground Based Augmentation Systems (GBAS) can correct the majority of the GNSS pseudo range errors experienced by an aircraft in the vicinity of an airport. The "normal" behavior of the ionosphere has a very limited impact on the position error; the confidence interval of the user position is fully acceptable for precision approach. Unfortunately, the ionosphere medium is sometimes subject to perturbations due to the strong temporal and spatial variability of the ionospheric plasma. While most of the time this environmental effect is behaving in a normal way, there has been found an anomalous ionospheric behavior which occurs rarely (few occurrences in 10 years) in mid latitudes but can be a serious threat to GBAS integrity. The CAT I GBAS architecture can principally not fully mitigate these effects by monitoring. In order to use the proposed mitigation algorithms for the ionosphere threat in a different geographical region, the anomalous ionosphere threat model has to be established for the relevant region. For the certification of a GBAS ground facility in Germany, both the anomalous ionosphere threat space and the nominal ionospheric decorrelation for a region including Germany were determined. This work has been done within the ITMA (ionosphere threat model assessment) project which is a joint project between the German Air Navigation Service Provider DFS and the German Aerospace Center DLR, funded by DFS.
Published in:	Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009) September 22 - 25, 2009 Savannah International Convention Center Savannah, GA
Pages:	1091 - 1099
Cite this article:	Mayer, C., Belabbas, B., Jakowski, N., Meurer, M., Dunkel, W., "Ionosphere Threat Space Model Assessment for GBAS," Proceedings of the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2009), Savannah, GA, September 2009, pp. 1091-1099.
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