# Comprehensive Review of UAV Detection, Security, and Communication Advancements to Prevent Threats
## 6 Security Threats Related to UAVs  
UAVs offer several perks as the technology advances, but still, there are some constraints associated with privacy, security, and safety concerns [35; 36]. Regularization and some important measures to license the utilization of drones is a very significant aspect. This limits unnecessary aerial photography. Most of the authorities in the world ensure this aspect and provide strict policies over uninformed aerial photography. If one discusses the network security point and the risk analysis, it is an admitted fact that the coverage is quite different as compared to any sort of wireless sensor network (WSN) or any mobile ad hoc networks (MANETs) [37]. The reason is because of the resource constraints, as UAV-related coverage is broader and wider than WSNs or MANETs.  
Figure 6: Utilization of drones in several domains.  
Figure 7: Malevolent and benevolent usages of a drone.  
The framework that sets the rules to operate drones in any vicinity is known as authentication, authorization, and accounting (AAA), which states several privileges to the controller of a drone to operate as per the mentioned administrative rights, whereas it also shares some of the rigid authentication procedures for drones to protect the control of a drone so that it may not be diverted to any other unknown entity. Moreover, in case of any uncertainty or illegal activity by drone, one may easily track down the operator. This is done to limit illegal surveillance, cyberattacks, and privacy threats. Thus, several mechatronic engineering solutions have been presented to overcome these malicious activities [38].  
These drones are low cost and easily available in markets nowadays, and therefore, they are easy to use for any sort of criminal activity. Their ability to carry a wide range of external payloads make them more dangerous as it could lead to drones carrying any harmful chemical or explosive thing. Moreover, their ability to reach places where normal human beings cannot makes them more lethal because they can deliver anything without coming under anyone's notice [39]. It should be noted that security is not the only concern, but one may also see a safety concern if drones are flying over any populous place and, due to any number of faults, may crash, which can lead to several types of tragedies [40]. These sorts of incidents have been reported often. One of the examples is when a UAV faced a collision with British Airways BA727, which was a passenger aircraft in April 2016. After looking over these incidents and issues, one may ensure below the mentioned public safety measures:  
* It is a high probability that a drone can be hacked or may deviate from its path due to heavy wind disturbance. Thus, there should be a reset option available which may turn the drone to a hovering condition only and help to gain the control back.
* There are certain areas where drones may face signal jammers and, later, can be controlled for a cyberattack. Thus, drones must have some sort of filter that may detect if there is any signal jammer nearby.  
The third safety measure is related to its design, as most drones have open propellers as shown in Figure 8. In case of uncertainty, these propellers may go off and may harm anyone nearby; thus, the safety design as shown in Figure 9 is necessary to avoid any harm during a crash.  
Lastly, there are some serious privacy concerns as well. Since UAVs on the market can easily be procured with high-definition cameras, this may lead to the recording of any  
Figure 8: UAVs with open propellers.  
Figure 9: UAVs with closed and safety propellers.  
private property without permission. Due to this reason, Canadian Public Safety (CPS) stated that these UAVs are prohibited from flying over any property without mutually agreed permission [41].