  In this paper, cyber attack detection and isolation is studied on a network
of UAVs in a formation flying setup. As the UAVs communicate to reach consensus
on their states while making the formation, the communication network among the
UAVs makes them vulnerable to a potential attack from malicious adversaries.
Two types of attacks pertinent to a network of UAVs have been considered: a
node attack on the UAVs and a deception attack on the communication between the
UAVs. UAVs formation control presented using a consensus algorithm to reach a
pre-specified formation. A node and a communication path deception cyber
attacks on the UAV's network are considered with their respective models in the
formation setup. For these cyber attacks detection, a bank of Unknown Input
Observer (UIO) based distributed fault detection scheme proposed to detect and
identify the compromised UAV in the formation. A rule based on the residuals
generated using the bank of UIOs are used to detect attacks and identify the
compromised UAV in the formation. Further, an algorithm developed to remove the
faulty UAV from the network once an attack detected and the compromised UAV
isolated while maintaining the formation flight with a missing UAV node.
