# UAV Support for Mission Critical Services
## 3 UAV Characteristics, Classifications and Commercial Deployments Status
### UAVs as Transportation Means  
The transportation capabilities of so-called \"delivery UAVs\" are dependent on their size and construction. Multi-rotor delivery UAV speed is typically limited to 60 km/h, and they can typically carry a payload of approximately 1.5 kg for 30 to 60 min of flight time [28]. In Table 4[22], the characteristic transportation capabilities of UAVs are provided. Postal companies have already used such drones, and they were used to transport medicinal products (blood products, vaccines and pharmaceuticals) in areas where the road infrastructure is not well-developed. In that context, it is worth mentioning the Zipline company, which, by October 2020, had made over 70 thousand medical deliveries by UAVs using fixed-wing electric UAVs [29]. There have also been attempts to use UAVs for food delivery. Wing [30] can carry parcels up to 1.5 kg and fly beyond the light of sight. Wing UAVs operates in some areas of several countries, including the USA, Australia and Finland, and by August 2021, they had delivered over 100 thousand parcels. An example of a powerful delivery UAV is the FB3 Heavy-Payload Cargo Drone [31] that is a multi-copter with eight rotors powered by rechargeable batteries. The UAV can carry up to 100 kg of a payload. Its empty weight is 70 kg, and it can fly from 10 to 40 min. An important problem concerning delivery UAVs is the lack of standardized hook mechanisms for transportation of parcels UAVs. Such a hook is needed for automated pickup and delivery of parcels. The delivery UAVs may play a significant role in MCS solutions; however, in some cases, it may be necessary to realize several UAV missions to deliver a solution composed of several components that have to be assembled at the destination. It concerns, for example, a portable base station composed of batteries, antennas, a solar panel and electronic units. Such a solution cannot be transported as a whole and should be assembled at the destination by a robot of a drone or a standalone robot delivered by a drone. Thus far, there are no solutions providing such capability. Moreover, a group of UAVs (swarm) can be used for the transportation of heavy loads. Such applications require the precise synchronization of UAV position and thus far is not in use. Most Beyond Visual Line of Sight (BVLOS) delivery UAV flights are autonomous (a flight is planned in advance); however, short-range, Visual Line of Sight (VLOS) flights can be manually operated. According to [32], delivery drones require low-bitrate links (<300 Kbps) and accept transmission delay ca. 500 ms.  
A typical Unmanned Aircraft System (UAS) consists of one or more UAVs and Ground Control Station (GCS) that is controlled or programmed by the UAV operator. In proprietary solutions, the GCS is connected to UAVs via radio link, typically using the Industrial, Scientific and Medical (ISM) radio band. Such a solution is popular in VLOS applications. There is ongoing research on the use of mobile networks for such communications--some 3 GPP recommendations define support to UAV communication and services by LTE and 5G mobile networks [33]. Typically, two communication channels are needed between the UAV and the UAV operator. The first one is named Command and Control (C2) and is used to control UAV position and collect flight-related information. The second link is related to the service offered by the UAV. It can be used for real-time video transmission from the onboard camera, transmitting data from sensors carried by a UAV, etc. The UAVs can be, to a certain \begin{table}
\begin{tabular}{l c c} \hline \hline
**Flight Mechanism** & **Multi-Rotor** & **Fixed-Wing** \\ \hline Mass (kg) & 0.01–100 & 0.1–400,000 \\ Payload (kg) & 0–50 & 0–1000 \\ Ceiling altitude (km) & 4 & 0.1–30 \\ Endurance (min) & 6–180 & 60–3000 \\ Range (km) & 0.05–200 & 3–35 \\ Energy source & battery & fuel or battery \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Differences between fixed wing and multi-rotor UAVs, after [22]. extent, autonomous.