Okuary Osechas

Vulnerability analysis of the CNS-infrastructure: An exemplarily approach

In this paper we identify security-related vulnerabilities of a few CNS-systems and describe their possible abuse by malicious agents replicating and broadcasting CNS (similar) signals, particularly for jamming and spoofing purposes. For communications, navigation and surveillance we consider VHF digital link mode 2, ground-based augmentation system and the secondary surveillance radar, respectively. In each case, we introduce a technical overview, identify susceptibilities and describe possible malicious attacks and their corresponding consequences. Finally, we present possibilities for minimizing risks emerging from exploiting the identified vulnerabilities of the considered system.

Integrated Inertial Navigation System with multiple APNT ranges: Expected performance and considerations

Inertial sensors constitute an essential part in civil avionics systems. It has also been identified as a required system to meet the foreseen availability requirements in the context of Alternative Position Navigation and Timing (APNT). For example, DME/DME/Inertial (DDI) is currently considered for RNAV 1.0 operations. In this work, we look beyond DDI and investigate the possibility of an integrated inertial system with multiple APNT ranges. Thanks to our simulation framework, we evaluate in different scenarios the integration of inertial system with ranging sources using real DME locations. Based on the results, we finally analyze and comment on the limitations, implications and issues of using tactical grade instead of navigation grade inertial sensors.

Improving the availability of LDACS-based APNT with Air-to-Air ranging

The currently envisioned plan for Alternative Position, Navigation, and Timing (APNT) relies heavily on Distance Measuring Equipment (DME) for providing RNAV/RNP services. Alternative proposals include the use of L-Band Digital Aeronautical Communications System (LDACS) signals as a means of obtaining ranging measurements, relative to a network of ground stations. We extend the LDACS-based approach to include the Air-to-Air (A2A) Communications capability, which has been specified for future implementation. Using A2A distance measurements between aircraft, potentially extends the availability of APNT. This is particularly interesting for low-altitude users (e.g. non-precision approach, departure) in the vicinity of high-altitude (e.g. en-route) users.

Placing LDACS-based ranging sources for robust RNP 1.0 accuracy en-route

Global Navigation Satellite Systems (GNSS) are becoming the primary means of navigation for civil aviation. Nevertheless, concerns about GNSS outages remain, driving the need for Alternative Positioning, Navigation and Timing (APNT) systems to provide availability and continuity for performance-based navigation services. Although the existing Distance Measuring Equipment (DME) infrastructure is able to provide Required Navigation Performance (RNP) 1.0 accuracy, it is not robust for individual station outages. Additionally, we show that in the European airspace DME is reaching the capacity limit. To address these two problems, we propose a methodology based on modular APNT. In the presented approach, the complementary ranging sources are optimally placed to obtain robustness. It is assumed that the L-Band Digital Aeronautical Communications System (LDACS) can provide this capability. As shown in the results, the modular APNT system is able to provide robust RNP 1.0 coverage for Germany using 17 new LDACS ground stations to complement the network of 73 existing DME installations in Germany.

Addressing vulnerabilities of the CNS infrastructure to targeted radio interference

Communication, navigation, and surveillance (CNS) technology is the backbone of modern-day air traffic management (ATM), containing a wide variety of radio systems that include ground stations, satellites, and aviation users. With the continuing development of software-defined radio, CNS systems are faced with a fundamentally new challenge that was not known at the time many of the systems were designed: software-defined radio has simplified the generation of radio signals with arbitrarily configurable modulation schemes and waveforms, to the point in which it has become financially accessible for private individuals.