Optimized Selection of Satellite Subsets for a Multi-constellation GBAS

Abstract

BIOGRAPHIES Daniel Gerbeth received a Bachelor and Master's degree in Electrical Engineering and Information Technology from Karlsruhe Institute of Technology in 2014. During Master studies he specialized in aerospace technology and navigation. After working in the field of sensor fusion and navigation aiding at Fraunhofer IOSB he joined German Aerospace Center (DLR) in May 2015 and is involved in the research on GBAS now. Michael Felux received a diploma in Technical Mathematics from the Technische Universität München in 2009. The same year he joined the German Aerospace Center (DLR) where he has was working on the development of the GBAS GAST C testbed at the research airport in Braunschweig and its upgrade to GAST D. He was involved in flight testing and ground validation of the station and the approach procedures. Since 2015 he is coordinating DLRs research on GBAS-based navigation.

Satellite selection in the context of an operational GBAS

“…Instead, the results and implications apply to any kind of satellite selection in GBAS. As the used algorithm in this work, we utilize our previously presented optimization method with slight modifications on the selection criteria in line with Walter et al Using an exhaustive search instead could change some of the results slightly, but as Gerbeth et al showed the heuristic algorithm to differ by well below 1% on average, we decided on a heuristic approach for the reason of inapplicable computation times otherwise.…”

“…This first set is iteratively optimized in a “greedy exchange” way. A detailed overview of this optimization can be found in Gerbeth et al…”

“…Details on the computation of the protection levels can be found in RTCA DO‐253D . As the absolute value of the achieved protection levels is also not of major interest in this study, but instead the relative changes due to different modifications on the selection, we will not go into details here and refer to the standards or our previous works instead …”

“…In terms of continuous operation of stand‐alone users, an approach was presented quite recently from Swaszek et al Similarly in Gerbeth et al, we already used the previously selected set as one of our starting sets for the optimization problems in continuous operation. If necessary, this can be even further simplified by performing a search for the best subset only in case of trigger events.…”

“…When a GBAS ground station makes a selection of satellites to broadcast corrections for, these factors should be considered instead of just selecting the satellites that lead to the best performance at a given epoch right at the ground station's location. While the topic of satellite selection in general has been largely covered very recently, this work is not limited to a specific selection algorithm but valid for any kind of selection. The objective is rather to show that satellite selection in GBAS is not largely affected by operational implications that cannot be avoided.…”