“…Unfortunately, standard protocols for formation control, that can be grouped into two families, neglect this aspect. In the first family of protocols, the leader or the follower UAVs can communicate all of their states among each other (position, velocity, orientation, linear, and angular velocity) [25], [36]- [38], which can lead to high communication overhead; in the second family of protocols, it is assumed that the leader UAV has unknown states and therefore a distributed observer is designed to estimate the unknown states [39]- [41]. Unfortunately, standard distributed observers also requires the communication of extra variables, which are the auxiliary states of the distributed observer: communication of these variables will inevitably lead to high communication overhead.…”