A Secure Broadcast Service for LDACS with Application to Secure GBAS

Kurzfassung

The VHF Data Broadcast (VDB) data link, responsible for transmitting Ground Based Augmentation System (GBAS) corrections from the GBAS ground station to the aircraft, is one major bottleneck for the evolution and security of GBAS. It provides limited bandwidth, range, only line-of-sight capabilities and no cyber-security protections for the transmitted data. Hence the use of an alternative data link for GBAS, overcoming these constraints, is desirable. The L-band Digital Aeronautical Communications System (LDACS) has been demonstrated to overcome aforementioned issues. The first demonstration of secure GBAS over LDACS used the Timed Efficient Stream loss-Tolerant Authentication (TESLA) for broadcast authentication of GBAS data. In flight trials, the concept and support of TESLA secured GBAS via LDACS for GAST-D services, supporting category II/III precision approach capabilities, was demonstrated. In this work, different ways are investigated to further optimize latency and security data overhead for an optimized transmission of TESLA secure GBAS packets via LDACS. Initial evaluation show how promising the different options are. Further it is shown how the developed concept for secure GBAS can also be applied to generalized secure broadcast over LDACS.