  This paper presents a new connectivity condition on the information flow
between UAVs to achieve coordinated path following. The information flow is
directional, so that the underlying communication network topology is
represented by a time-varying digraph. We assume that this digraph is connected
in an integral sense. This is a much more general assumption than the one
currently used in the literature. Under this assumption, it is shown that a
decentralized coordination controller ensures exponential convergence of the
coordination error vector to a neighborhood of zero. The efficacy of the
algorithm is confirmed with simulation results.
