Real-Time Safety Assessment of Unmanned Aircraft Systems Against Stealthy Cyber Attacks

As unmanned aircraft systems become an increasingly integral part of a wide range of applications, ensuring the security of these systems against malicious cyber attacks is a very important concern. To address this problem, this paper considers a controls domain approach extending beyond the computing resources of the unmanned aircraft system to include the underlying physical behavior of the compromised system, successfully complementing the traditional computer security architecture. Specifically, the focus is on the safety analysis of an unmanned aircraft system in the presence of stealthy cyber attacks, which can be designed intelligently to avoid detection. First, the system condition that confines the stealthy attacker's capability is derived. Then, a real-time safety assessment algorithm is developed based on a reachability analysis. Compared to the existing research, the present algorithm analytically derives the exact reachable set, enabling more reliable and computationally efficient safety assessment. The proposed safety assessment algorithm is demonstrated by illustrative examples with different attack scenarios