Secure State Estimation and Attack Identification for Cyber-Physical Systems with Event-triggered Communication against FDI Attacks

Cyber-physical systems (CPSs) signify a groundbreaking evolution in the realm of sophisticated interactive systems. However, the widespread application of CPSs has brought significant security concerns due to their inherent vulnerabilities to malicious networked assaults. In order to overcome the effect of such attacks on CPSs, this paper investigates the problem of secure state estimation and attack identification for CPSs equipped with multiple sensors under random false data injection (FDI) attacks. First, by incorporating the attack signal as a part of the system, we design a secure state estimator with augmented states that enables simultaneous accurate secure state estimation and precise attack identification. An event-triggered communication strategy based on measurement residual is introduced to determine whether measurement data should be transmitted. Compared to the traditional communication mechanism, the proposed event-triggered communication can effectively decrease the data transmission requirements of CPSs. The final estimation algorithm, which includes the secure estimator with augmented states and the event-triggered communication mechanism, is derived by solving a partial differential equation. Finally, some numerical simulations of a practical example are provided to demonstrate the effectiveness of the proposed method.