Published:
2026, Transportation Research Procedia, Amsterdam, Elsevier B.V.), p. 129-140), ISSN 2352-1465
Annotation:
In Automatic Dependent Surveillance–Broadcast (ADS-B) messages, the CA field indicates the on-ground/airborne status, which determines whether surface or airborne messages should be sent. An incorrect setting of this status, sometimes also referred to as the ground bit setting (based on the ASTERIX data format), can have negative implications for air traffic management or the functioning of onboard anti-collision systems. In this paper, the behavior of the ground bit in data from real airport operations is analyzed and the validity of the ground bit changes is evaluated. An ADS-B dataset covering 8 days of operations at Václav Havel Airport Prague (LKPR) in January 2024 was used for this purpose. Within the dataset, a total of 2,185 ground bit changes were analyzed individually. It was found that 9.1% of all ground bit changes during this time, corresponding to 13.0% of unique aircraft, were not valid in terms of representing the aircraft runway movements (take-offs and landings). Besides valid ground bit changes, fluctuations leading to false changes were observed, particularly during landings, as well as anomalous ground bit changes which often occurred within the apron areas and were completely unrelated to the runway movements.