Attack Detection for Multisensor Cyber–Physical Systems With Unknown-But-Bounded Noises: A Zonotopic Approach

This article investigates the attack detection for multisensor cyber–physical systems with both secure and insecure sensors as well as unknown-but-bounded noises based on a zonotopic approach. Based on the intersection of the predicted state set and the secure measurement state set, we construct the security state set to detect attacks on insecure sensors. Then the attacks can be detected by judging whether the intersection of the security state set and insecure measurement state set is empty. Then, we provide a sufficient condition to guarantee that the detection performance of our proposed method is better than that of the predicted state set-based method. Furthermore, we propose a watermarking-based detection method to detect attacks whose amplitude is within the zonotope of the measurement noise, and randomly select the watermarking within a center-constrained zonotope. The watermarking is utilized to ensure that the measurement output with watermarking is not equal to zero, which can enhance the detection performance of our proposed method. Finally, a numerical simulation is provided to demonstrate the effectiveness of theoretical results.