Byzantine-resilient distributed state estimation: A min-switching approach

Abstract

This paper proposes two distributed state estimation protocols for static linear cyber–physical systems under Byzantine links/nodes caused by adversarial attacks. First, a basic version of secure distributed algorithm is proposed where the influence of the Byzantine links/nodes is countered by adopting a local min-switching decision (LMSD) rather than the existing coordinate-wise trimmed means (CWTM). Necessary and sufficient conditions on the network connectivity are provided to guarantee all the regular nodes asymptotically converge to the least square estimate of the system state in the presence of a certain number of Byzantine links/nodes and sensor noises. Further, by adopting event-triggered and minimum subset decision techniques, an improved low-complexity algorithm is proposed that allows the LMSD to be intermittently performed with average linear complexity. A main advantage over the existing CWTM-based algorithms is the use of the LMSD mechanism to significantly reduce the network connectivity requirements and do not assume any observability conditions on the local nodes.