  This paper investigates the problem of communication relay establishment for
multiple agent-based mobile units using a relay vehicle. The objective is to
drive autonomously the relay vehicle to attain a position for communication
relay establishment while maintaining the other vehicles inside of its
field-of-view. A bearing-based control law is proposed for the relay drone and
designed for both single and multiple agents. We also provide a collision
avoidance scheme that ensures no collisions between the relay and other agents.
Numerical simulations and experimental results are reported as well to show the
efficacy of the proposed approach.
