Distributed Secure State Estimation for FDI Attacks in Interconnected Cyber‐Physical Systems

ABSTRACT This paper investigates the distributed secure state estimation problem for interconnected cyber‐physical systems (CPSs) under false data injection (FDI) attacks. Firstly, we introduce intermediate variables and output estimation feedback terms for sensor attacks and actuator attacks, and propose two intermediate observer systems based on the proposed two intermediate variables of sensor attacks. The agent dynamic error system is derived based on the estimation error of the state and intermediate variables. Then, the performance index is utilized to suppress FDI attacks, and the robustness condition and error convergence boundedness of the system errors are proposed, by which observer gain matrices can be solved in terms of linear matrix inequalities. The proposed distributed secure state estimation approach, based on the original system matrix framework, offers a significant improvement over previous methods, which rely on augmented system models. It substantially reduces the communication burden, enhances the flexibility and adaptability of the design, and ensures robustness and uniform boundedness against system errors. Finally, the effectiveness of the proposed method is validated through numerical simulations.