  In this paper, we present a scheme of fully distributed resilient state
estimation for linear dynamical systems under sensor attacks. The proposed
state observer consists of a network of local observers, where each of them
utilizes local measurements and information transmitted from the neighbors. As
a fully distributed scheme, it does not necessarily collect a majority of
sensing data for the sake of attack identification, while the compromised
sensors are eventually identified by the distributed network and excluded from
the observers. For this, the overall network (not the individual local
observer) is assumed to have redundant sensors and assumed to be connected. The
proposed scheme is based on a novel design of a distributed median solver,
which approximately recovers the median value of local estimates.
