# Power Sources for Unmanned Aerial Vehicles: A State-of-the Art
## 2 Unmanned Aerial Vehicle (UAV)
### Fuel Cell Powered UAVs
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**Power Supplying Technique** & **Advantages** & **Limitations and Drawbacks** \\ \hline The concept of wireless refueling offers significant advantages for UAVs, including the potential for unlimited operating time and extended mission durations. With this approach, UAVs can receive a continuous supply of power without the need to land or swap batteries. This eliminates the limitations imposed by battery capacity and enables persistent missions. & While wireless refueling using laser beams offers potential benefits for UAVs, there are certain constraints and considerations that need to be addressed. One of these constraints is the necessity of a ground station (CS) equipped with a laser transmitter to provide power to the UAVs. This means that the UAVs need to operate within a reliable power transfer. This range limitation can restrict the operating area of the UAVs and may not be suitable for missions that require long-range coverage or operations in remote areas. & Another constraint is related to the operating heights of the UAVs during laser beam recharging. In order to maintain a consistent power transfer, the UAVs typically need to operate at reduced heights, which can be influenced by regulations and safety considerations. For instance, the Federal Aviation Administration (FAA) sets maximum altitude restrictions for small UAVs, limiting their operating height to 400 feet. Compliance with these regulations may further restrict the altitude range for UAVs using laser beam refueling. & Obstruction of the laser beam is another consideration. The laser beam used for refueling needs a clear path between the GS and the UAV. This means that obstacles such as buildings, trees, or other structures can obstruct the beam, potentially interrupting the power transfer. Careful planning and positioning of the GS and the UAVs are required to minimize the risk of obstruction and ensure a reliable power supply. \\ \hline \end{tabular}
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Table 3: _Cont._In addition to providing power, wireless refueling also enables safe and effective data transfer between the UAV and the ground station. Along with power, the laser beam can be used to transmit data and communication signals, ensuring seamless connectivity and information exchange between the UAV and the ground control. The ability to operate continuously and receive power and data transfer wirelessly offers several advantages. It enables UAVs to perform long-duration missions without interruption, making them suitable for applications that require persistent surveillance, monitoring, or data gathering. It also reduces the logistical challenges and risks associated with manual battery replacement or refueling operations, as the UAVs can remain in the air and operational throughout their mission. Moreover, wireless refueling contributes to increased safety by eliminating the need for frequent take-offs and landings, which can be risky maneuvers for UAVs. The continuous operation and avoidance of landing procedures minimize the chances of accidents or incidents during mission execution. Overall, wireless refueling with a single energy source provides UAVs with the capability for unlimited operating time, persistent operation, safe data transfer, and reduced reliance on ground-based support. These advantages make it an attractive solution for various applications where extended flight durations, continuous operation, and efficient data transfer are essential. Overall, while wireless refueling offers advantages, such as unlimited operating time and eliminates the need for landing or battery replacement, it comes with certain limitations. One of these limitations is the necessity of a ground station (GS) to provide the power supply or laser transmitter. The GS serves as the central hub for supplying power or transmitting the laser beam to the UAV in flight. Additionally, wireless refueling methods often have constraints related to the operating area of the UAV.