- High mobility
- Increased reliability & quality of services
- Ubiquitous coverage
- Robust security Radio Division.
Numerous telecom companies are conducting trials for UAS operation in cellular LTE network and consequently, the problems faced are [26]:
- Optimization of the cellular requirement for drones: Cellular networks are needed to be distinguished from the one which is currently in use by worldwide users for optimal operation (e.g. Noise avoidance) of UAs in cellular networks.
- Handover optimization: While in operation it is obvious UAs are going to receive signals from multiple base stations. Therefore, handover will be frequent which will lead to heavy signaling overheads.
- Interference mitigation: When airborne UA will receive signals from multiple base stations hence there will be interference.
1.4 Application of UAV
UAVs have an immense possibility to be used widely in both military and civil applications because of economic viability, safety benefits, and high mobility. Recent technological advancements in UAVs have made it more compatible for replacing the manned aerial vehicles and even outperforming them in many tasks and at the same time proving its worth in the commercial market is also commending.
1.4.1 In Military
Nikola Tesla, in 1898, first developed which was arguably the first remote-controlled unmanned vehicle, also called ‘Teleautomation’, a boat controlled by radiofrequency. From those humble times, unmanned systems have undoubtedly achieved a huge milestone. In today, UAVs accomplish many missions and roles in the service of the military as well as in other sectors. Military are currently the principal operators of UAVs employing the paramount technologies including stealth features. Primary military drones include services like ISR (Intelligence, Surveillance, and Reconnaissance) or light attack functions. They range from small or medium tactical drones to high-altitude, the long-endurance once. Combat-enabled drones, like the armed version of reaper or predator, can carry out light attacks or against light-ground targets which are also widely reported in Libya and Afghanistan [27].
UAV can be used for military missions “Dangerous, Dull, dirty” as there is no loss of life asset. Also, robots don’t mind circling a particular area for a dozen hours and can be operated in military and civil environments. They are also used to carry notorious missions of surveillance, security, and attack. In today’s world, the term ‘Unmanned Aerial’ has gained so much acceptance, and when these things are combined with a ground control station and a communication channel (or data link) they constitute UAS. Nowadays, UAS are cheaper to operate, procure, and maintain when compared to manned aircraft with some limitations. As they eliminate the risk of a pilot’s life while in operation and their capabilities like endurance aren’t constrained by human limitations [28]. However, in the future, they could be used for air-refueling, resupply, air combat, and search and rescue operations. The remote operation of UAS has been made more practical because of the availability of advanced navigation and satellite communication technology. The capability of UAV to loiter, search & strike the targets while minimizing the collateral damage, makes this thing an indispensable weapon. Its features are further enhanced by using multispectral thermal and night vision state of the art cameras and better remote control allows the UAS to take on more reconnaissance roles. Today’s UAV can remain on a mission for 30–40 h, far beyond the capabilities of any human crew. Research into ultra-efficient solar power and in-flight refueling could help in increasing the range of UAVs, limited primarily by maintenance needs.
1.4.2 In Geomorphological Mapping and Other Similar Sectors
Topographic surveys are important from the point of view of the study of earth surface dynamics and processes. These types of surveys are often required for huge (>11 km2) areas at a relatively higher temporal resolution which can be used in monitoring the ecological change, hazard monitoring, or any kind of detailed process studies [6].
The geomorphic study includes the study of landforms, their classification, origin, development, and history which can be done through acquiring high-resolution topographic data which holds the key to many studies and discoveries in Earth sciences including that of earth surface processes and dynamics. For mapping, studies that require data at high temporal (hourly or daily basis), and large spatial (>10 km2) scales, these traditional surveying methods are often time-intensive and costly. However, recent development and changes in technology have seen a rise in digital photo-grammetry as a viable means of obtaining high-resolution topographic data [6].
Such advancement in technologies and increase in affordability of UAVs makes it a novel platform for low-level aerial photography which can be done whenever needed for such photogrammetry in geomorphological studies where traditional methods like satellite imagery might not work. Moreover, it has also various applications where a similar type of work is involved like in filmmaking, scientific research, surveying, mining, cargo transport, forestry and agriculture, journalism, aerial surveillance, etc.
1.4.3 In Agriculture
Farmers can use the agricultural drone to spray pesticides, fertilizers, and other chemicals. Special cameras and sensors can be used to spot problems in the crops. Diseased parts of the crop can be spotted early. Different types of data related to the farm, crop, land, and atmospheric conditions can be collected. This data is used to ensure healthy crops and successful harvest [29].
1.5 UAV Challenges
UAVs are of significant use for various novel activities. However, when it comes to the regulation of flying small drones it becomes a challenge. There are thousands of small drones that are sold worldwide. A small drone can be built even by a novice using parts available from the internet. A small drone can also pose a high safety risk to large planes, fuel depots. Losing control by drone operators is an occasional instance. There isn’t any severe accident so far reported but there are some criminal reports in which drone is used to supply illegal and banned items into prisons or targeted area. Even the insurance aspect is not fully defined or developed. There is also the risk of privacy as drones can be used to spy over someone without his/her knowledge, look inside a home through windows, can fly high and record visible parts of the property. However, government authorities have been trying to reduce
