Figure1: Possible solutions to recharging drones
A combination of an optical sensor such as the camera on board the drones and ground-based beacons could be used for accurate relative position determination to allow a precision landing. This could be useful for landings, take offs, indoor navigation and loitering without GPS. They plan to use GPS to travel to a waypoint, and then use the IR-LOCK sensor to land precisely on an infrared beacon. The solutions proposed for recharging station combined with solar cells and wireless energy transfer aiming to keep drones in the air much longer. Solar cells is more efficiency, there is not need to aligning the drones to recharging station. Wireless (or inductive charging) requiring drive electronics and coils in both the device and charger. Wireless energy transfer has numerous benefits it is useful in indoor/outdoor environment, can recharge any type of battery Li-PO, NiMH. On the contrary, one of the reasons because wireless charging has not been fully integrated is due to the lower efficiency, devices take a longer time to charge when supplied with same amount of power. Moreover, to reduce the losses a perfect alignment between transmitter and receiver on board UAVs is mandatory. Sky-Sense Company presents a solution that is more efficient. Charging pad. It is a tessellation of conductive tiles. When the drone lands, a physical contact between the plate and two spring-loaded attached to the bottom of the drone allows to charge the batteries. The common disadvantage of this solution is that the system need a Battery Balancing System on board UAVs ( extra weight is added). The aim of multiple unmanned autonomous vehicles (UAVs) in coordination is to locate the missing person in less time, and in less time than flight time of single UAV. In search and rescue operations, every second counts. Imagine having a large area the UAVs can share a common map, communicating to each other the position already monitored and choosing in real-time the next position to be visited. UAV swarms increasing our probability of success and efficiency by deploying more than one search vehicle at a time. The greater number of vehicles able of monitoring a wide area has as consequence less time it will take to locate our target. This is checked in the equation: