Improved Interval Estimation Method for Cyber-Physical Systems Under Stealthy Deception Attacks

This paper investigates the problem of interval estimation for cyber-physical systems subject to stealthy deception attacks. The cyber-physical system is supposed to be compromised by malicious attackers and on the basis of that, a stealthy attack strategy is formulated. Moreover, the stealthiness of the attack strategy against $\chi ^{2}$-detector is analyzed. To accomplish interval estimation, the interval observer is designed by the monotone system method. Then, a novel method which combines reachable set analysis with $H_{\infty }$ technique is proposed. Theoretical comparison between the monotone system method and the proposed method is presented and it shows that the proposed method is able to improve the estimation accuracy. Finally, two illustrative examples are provided to demonstrate the superiority and effectiveness of the improved method.