## 4 Avinomics Assessment
### Power  
As can be seen in Figure 1, the power subsystem is the most critical amongst all the others, representing the operating fuel for every SBCs, SoM, communication, and each sensory module. A UAV's flight pace and duration are mainly dictated by the offered energy level from the power subsystem. In order to successfully overcome limited flight endurance, the power system must be carefully chosen, mainly based on the UAV's purpose of flight. For example, a search-and-rescue UAV requires more power than the one used to assess public infrastructure since the first often interacts with spontaneous incidences of high risks. Generally, the power source of a UAV must be chosen according to its durability, it must have a good energy to weight ratio and create as minimum noise and vibrations as possible, and it must be easily replaced. Conventionally, UAVs are powered with batteries, battery hybrids with proton membrane fuel cell, gasoline engines, hydrogen fuel cells hybrid with Lithium-Ion batteries (Li-I), and solar power.  
Beginning with the work in [298], a 14 kg UAV had a power of 960 W supplied from a hybrid system, which was composed of a proton-exchange membrane fuel cell (as the main supply) and a Li-I (as a backup). This power-source mixture took advantage of the fuel cells fast refueling and ability to supply power for long distance ranges, in addition to the Li-I high acceleration and fast response to load variations. Such a power scheme, however, may present concerns regarding its longevity under frequent charging/discharging of the Li-I. An alternative way to overcome the UAV's battery capacity issue and the need for its frequent charging is Droneport [299]. It consists of a landing platform, over which the UAV can have its battery exchanged and charged outside of its frame. As an alternative to hybridization with other-than-battery power sources, Droneport represents a complete electromechanical system, as shown in Figure 10, enriching the capabilities of UAVs with existing batteries power sources.  
Unlike the study in [298], the work in [300] suggested a hybridization between gasoline and electric motors: two gasoline motors supplied the majority of the power needed for the lift force, with four electric motors utilized to stabilize the drone. Since the propellers consume the majority of the power within a UAV, the suggested gasoline-electric hybrid method prolongs a UAV's flight time. Apart from gasoline, electric, and hybrid power sources, UAVs can be solar powered. In reference [301], a 2 m wingspan UAV was powered through a combination of solar PhotoVoltaic (PV)-based power and a battery. Under fair weather conditions, the solar-battery hybrid system saved up to 22.5% of the battery stored capacity.  
Solar-based power supplies for UAVs are generally inconsistent since they mainly depend on solar irradiance, which can be very fluctuant. Even during sunny days, cloud-induced Partial Shading Conditions (PSCs) [302] impose great challenges in extracting the maximum available power from PV modules. Gasoline-based power strategies, on the other hand, induce fire hazards and higher maintenance requirements, regardless of the extended flight capabilities. Modern research in Li-I optimization would constitute an optimum alternative for traditional as well as hybrid UAV power sources, concerning weight restrictions, explosiveness, extended Depth of Discharge (DoD), and other factors [303].