Event-triggered distributed hierarchical secure estimation under DoS attacks

This article is concerned with the issue of distributed hierarchical secure estimation over wireless cluster networks under denial-of-service (DoS) attacks. Here, communication interactions rely on hierarchical networks with local wireless sensor networks in the first layer and wireless cluster networks in the second layer. To reduce communication consumption over local wireless sensor networks, recursive event-triggered sequential local estimators are first proposed in each cluster head (CH) by the codesign of an event-triggered scheduling mechanism and sequential local estimators. So only necessary measurements are transmitted to the CH in an individual cluster. A distributed hierarchical estimator is further derived by fusing intercluster local estimates over wireless CH networks under DoS attacks, where the attack model is characterized by average frequency and duration. Then, a detailed performance analysis for the designed distributed hierarchical secure estimator is conducted. Specifically, the uniform boundedness of the distributed estimation covariance and the convergence of the distributed hierarchical estimator are discussed for collectively observable wireless CH networks. Finally, both numerical simulation and practical experiment of a real unmanned surface vessel tracking system are shown to verify the proposed techniques.