Design of functional interval observers for linear continuous systems under stealthy attacks

To address the issue of secure state estimation in networked control systems, this paper investigates the design of functional interval observers for linear continuous systems under stealthy attacks. Initially, by analyzing the inherent characteristics of stealthy attacks, the boundary information of the attack signals is derived. Subsequently, grounded in filtering theory, we propose a robust functional observer for linear continuous systems to mitigate the impact of unknown disturbances. Thereafter, to furnish a precise interval estimation of the system under stealthy attacks, a functional interval observer is introduced employing interval analysis of the attack signals and system states. Ultimately, the accuracy of the proposed method is validated through numerical simulation results.