  Unmanned Aerial Vehicles (UAV)-based civilian or military applications become
more critical to serving civilian and/or military missions. The significantly
increased attention on UAV applications also has led to security concerns
particularly in the context of networked UAVs. Networked UAVs are vulnerable to
malicious attacks over open-air radio space and accordingly, intrusion
detection systems (IDSs) have been naturally derived to deal with the
vulnerabilities and/or attacks. In this paper, we briefly survey the
state-of-the-art IDS mechanisms that deal with vulnerabilities and attacks
under networked UAV environments. In particular, we classify the existing IDS
mechanisms according to information gathering sources, deployment strategies,
detection methods, detection states, IDS acknowledgment, and intrusion types.
We conclude this paper with research challenges, insights, and future research
directions to propose a networked UAV-IDS system which meets required standards
of effectiveness and efficiency in terms of the goals of both security and
performance.
