Survey on Coverage Path Planning with Unmanned Aerial Vehicles <s> Decentralized Technique <s> This paper proposes a distributed approach to solve long duration area surveillance missions with a team of aerial robots, taking into account communication constraints. The system, based on “one-to-one” coordination, minimizes the probability that any event happens in the area without being detected and ensures periodic communication between UAVs. A set of simulations are presented to validate the applicability of the approach and its most relevant features: convergence, robustness with dynamic teams, fault-tolerance and finite information sharing time. It is also shown that “one-to-one” coordination for all the pairs of neighbors allows to obtain an efficient coordination scheme for the whole team to accomplish the area surveillance mission without any central unit. <s> BIB001 </s> Survey on Coverage Path Planning with Unmanned Aerial Vehicles <s> Decentralized Technique <s> Using aerial robots in area coverage applications is an emerging topic. These applications need a coverage path planning algorithm and a coordinated patrolling plan. This paper proposes a distribut... <s> BIB002 </s> Survey on Coverage Path Planning with Unmanned Aerial Vehicles <s> Decentralized Technique <s> This paper presents a decentralized algorithm for area partition in surveillance missions that ensures information propagation among all the robots in the team. The robots have short communication ranges compared to the size of the area to be covered, so a distributed one-to-one coordination schema has been adopted. The goal of the team is to minimize the elapsed time between two consecutive observations of any point in the area. A grid-shape area partition strategy has been designed to guarantee that the information gathered by any robot is shared among all the members of the team. The whole proposed decentralized strategy has been simulated in an urban scenario to confirm that fulfils all the goals and requirements and has been also compared to other strategies. <s> BIB003
A decentralized algorithm for partitioning rectangular areas during surveillance missions is presented by Acevedo et al. BIB001 . Homogeneous vehicles distribute the sub-regions using a one-to-one coordination technique and explore adjacent areas. The vehicles have a short range of communication, as shown in Figure 16 , and must share information passing by near points in a synchronized way. The sub-regions are equally distributed with paths of the same size generated by the sub-perimeter method. This method developed by the authors uses the information about the area to generate an interior similar region, such that the maximum distance from the inner zone to the border of the area is less or equal than the coverage range. The system is adaptable to modifications in the team, such as a departure of a vehicle for repairs or a battery recharge. The main goal is to develop a cooperative patrolling strategy to optimize the observation interval among consecutive attempts in any spot and minimize sharing time of detected information with the other members (latency). More recently, Acevedo et al. BIB002 extend their approach for surveillance in irregular-shaped areas with heterogeneous vehicles. The irregular area contains obstacles and irregular borders, thus it is discretized into regular regions, as shown in Figure 17a . The numbered black rectangles in this figure represent forbidden flight zones used to delimit boundaries and indicate obstacles. In this context, instead of partitioning the area of interest, a single path that covers the entire region is segmented and distributed to the vehicles, sharing information among the neighbors. Faster vehicles cover larger path segments and all vehicles invert the patrolling direction at the end of each part. In simulations, an urban scenario with constructions is considered, as illustrated in Figure 17b , with four vehicles flying in low altitude, while avoiding obstacles. The system is able to adapt itself to the entrance and the exit of vehicles during the mission. Finally, Acevedo et al. BIB003 explore the one-to-one coordination approach using a grid-shape area partition strategy. The area of interest is partitioned into non-overlapping sub-regions monitored by heterogeneous vehicles following distinct paths. This technique allows the vehicles to self-adjust the partitioning according to their maximum capacities, maintaining the synchronization in a distributed and decentralized way. Furthermore, this solution is able to rearrange primary conditions, such as area shape and vehicles capacity.