  The threats on cyber-physical system have changed much into a level of
sophistication that elude the traditional security and protection methods. This
work addresses a proactive approaches to the cyber security of a formation
flying UAVs. A resilient formation control of UAVs in the presence of
non-cooperative (defective or malicious) UAVs is presented. Based on local
information a resilient consensus in the presence of misbehaving nodes is dealt
with fault-tolerant consensus algorithm. In the proposed framework, a
graph-theoretic property of network robustness conveying the notion of a direct
information exchange between two sets of UAVs in the network is introduced to
analyze the behavior and convergence of the distributed consensus algorithm. A
distributed control policy is developed to maintain the network connectivity
threshold to satisfy the topological requirement put forward for the resiliency
of the consensus algorithm. Numerical examples are presented to show the
applicability of the proactive approach used in dealing with the cyber attack
treat on a formation flying UAVs
