## 3 Prototype Description and Implementation
### Requirement Analysis  
One of the main challenges found in he reviewed literature was the fact that the UAVs used for livestock monitoring were not specifically conceived for this purpose. While they are capable on their own to perform most of the functionalities expected from them, there are several facts that have not been taken into account and may result into issues:  
1. Security is a must in the UAV. The components that make the UAV should have as many security features as needed, so that its usage will not result into any kind of cyberattack becoming successful and either during the UAV away from their owners or damaging the hardware components used for its normal operating. This makes the idea of building a UAV from scratch more attractive, as it is possible to have a better knowledge of the security embedded in each of the components. 2. Security is a must in the deployed subsystems. Not only the UAV must be secured, but also the infrastructure used to secure the data delivery and transfer. To accomplish this purpose, there are several actions that can be taken: to begin with, the data storage infrastructure can become decentralized, so that it becomes obvious when one of the parties is trying to modify the data with malicious intentions. With such an infrastructure, integrity of the information uploaded (images, video) can be guaranteed and farmers can display the location and characteristics of the livestock whenever they are grazing, along with identifying potential predators o rother threats. 3. Range for monitoring. Wireless communication protocols have features related to signal power, range and data transmission, which also impose restrictions on what  
Figure 1: Theoretical model for the system proposal. power a UAV needs to perform its functionalities and might come in conflict with using a UAV as simple as possible. Using a UAV with limited capabilities for the purpose shown in this manuscript might be desirable due to two reasons: budget (a simpler, more basic UAV will be cheaper to deploy and will required not too skilled workforce) and legislation (current legislation might be too restrictive for small or medium-small UAVs, but more lenient on smaller UAVs, which will make them easier and faster to use in the latter case). 4. Mission autonomy. Energy for UAV movements and communications is drawn from a built-in battery that requires being recharged before it comes to depletion. With not enough battery energy, the UAV purpose might become jeopardized if flight autonomy is too small, thus forcing to either having a recharging infrastructure in the location where monitoring is taking place, or to make short-timed monitoring missions that might miss some of the animal actions. 5. Closed, regular commercial solutions are harder to fix in the countryside. While already built solutions are easier to maneuver as a UAV pilot and offer a level of quality that more oriented Do-It-Yourself developments cannot compete with, its closed nature makes it more difficult to repair in case the UAV results damaged from operating with it. It must be born in mind that livestock monitoring might take place in remote locations (as it has been reviewed in the literature shown in the previous section), so having to take the UAV to an official maintenance service branch might be challenging for the kind of missions that are performed. This, in turn, will likely force farmers to own more than one UAV as a closed solution, thus resulting in extra budgetary needs. Building a UAV from scratch solves that issue to an extent, as there are others related to security and legislation that might appear. 6. Animal behaviour can be challenging. Due to the behaviour of animals when monitored with an alien, unknown element that seems to behave in an unsettling manner (high-pitched noises, hovering), livestock tends to become uneasy and even frightened around UAVs at first, to become indifferent once they have adapted to the UAV presence afterwards.