Cyber Security Analysis for State Estimators in Air Traffic Control Systems

Abstract

Cyber security has emerged as one of the most important issues in modern Air Traffic Control (ATC) systems whose functionalities heavily rely on communications between networked agents in the system. Since the current ATC systems has not incorporated mechanisms specifically designed to protect their cyber security, potential cyber attacks such as GPS spoofing, false data injection and computer virus may threat the safety of the systems. This paper is focused on the cyber security of linear state estimators (Kalman filters) which are widely used in ATC systems for aircraft surveillance and control. Compared with other components in the ATC system, state estimators can be more easily attacked because they directly process the raw sensor and communication data which can be directly falsified by cyber attacks. Since cyber attacks rarely happen, accurately modeling cyber attacks is usually intractable. Therefore, this paper analyzes all possible attack cases to identify the estimator’s security hole in the worst case. Specifically for a class of linear estimators, namely, the α−β filter, which has wide applications, the optimization tools are used to identify the most dangerous attack sequence among all stealthy cyber attacks. The approach proposed in this paper is general and can be applied to other systems’ security analysis.