Secure distributed filtering for unstable dynamics under compromised observations
It addresses the problem of secure state estimation in distributed networks with malicious attacks, offering theoretical guarantees for unstable dynamics.
This paper proposes a secure distributed filter for unstable linear systems under compromised observations, using a saturation-like scheme and consensus to ensure bounded estimation error. A sufficient condition for error boundedness is established, linking to 2s-sparse observability.
In this paper, we consider a secure distributed filtering problem for linear time-invariant systems with bounded noises and unstable dynamics under compromised observations. A malicious attacker is able to compromise a subset of the agents and manipulate the observations arbitrarily. We first propose a recursive distributed filter consisting of two parts at each time. The first part employs a saturation-like scheme, which gives a small gain if the innovation is too large. The second part is a consensus operation of state estimates among neighboring agents. A sufficient condition is then established for the boundedness of estimation error, which is with respect to network topology, system structure, and the maximal compromised agent subset. We further provide an equivalent statement, which connects to 2s-sparse observability in the centralized framework in certain scenarios, such that the sufficient condition is feasible. Numerical simulations are finally provided to illustrate the developed results.