Trust-Based Distributed Secure State Estimation Against Malicious Agents via Two-Hop Communication

This article studies the distributed secure state estimation problem in unreliable multiagent networks through adversary detection. The agents are endowed with the capacity for detecting malicious neighbors and aim to collaboratively estimate the state variables of a dynamic system in the presence of malicious agents. A trust mechanism is first introduced to characterize the reliability of the information received from in-neighbors and identify the reliable information of two-hop in-neighbors. With the help of the trust mechanism and two-hop communication, two distributed secure state estimation schemes with adversary detection algorithms are developed under different resource requirements and adversary models. Necessary and sufficient conditions on the graph connectivity and joint detectability are established to guarantee that all the regular agents can detect the malicious in-neighbors and generate accurate estimates. An example is given to show the effectiveness of the proposed methods.