Patrolling a terrain with cooperrative UAVs using Random Walks

A group of UAVs can be used to efficiently patrol a terrain, in which each robot flies around an assigned area and shares information with the neighbors periodically in order to protect or supervise it. To ensure robustness, previous works propose sending a robot to the neighboring area in case it detects a failure. In order to add unpredictability and to improve on the efficiency in the deterministic patrolling scheme, this paper presents random strategies to cover the areas distributed among the agents. We evaluate these strategies using three metrics: the idle-time, the isolation-time and the broadcast-time. The idle-time is the expected time between two consecutive observations of any point of the terrain. The isolation-time is the expected time that a robot is isolated (that is, without communication with any other robot). The broadcast-time is the expected time elapsed from the moment a robot emits a message until it is received by all the other robots of the team. Simulations show that the random strategies outperform the results obtained with the deterministic protocol.