# The Use of Drones in Spain: Towards a Platform for Controlling UAVs in Urban Environments
## 4 Proposed System  
At the technical level, therefore, we will still have to wait for some time until commercial UAVs can be adapted to a judicial process, such as the one considered in the previous section. However, our work with UAVs started back in 2011 and much of our time has been dedicated to the development of a software platform that would monitor and record the parameters obtained by connected UAVs in a central system. The main objective of this work is to make the developed platform suitable for type of existing commercial UAV, so that they can enjoy added functionality (autonomous flights, different security mechanisms, telemetry storage, etc. ), while ensuring that all their flights abide to current law. Thus, when developing this system, we first analyzed the different existing UAV systems and looked for a way to integrate them in a single platform. The best solution is to design a module capable of communicating with our platform, integrating all the functionalities, and enabling the control existing types of commercial UAV as if the platform itself were the pilot. The chosen solution is described in more detail throughout this section. To connect with the platform, only one hardware module must be incorporated into the UAV. This module connects with the communication infrastructure deployed in the city and allows the UAV to be controlled in a traditional way, with radio controllers or commercial Ground Control Stations (GCS). UAVs can also be controlled manually or autonomously through the developed software. A gamepad is used for manual control, while configurable waypoints or advanced behaviors are defined for autonomous control. Wi-Fi communication is the solution for this platform, it allows to monitor all telemetry of the connected aerial vehicles and control them, when their behavior has to be altered for security or privacy reasons. The use of Wi-Fi communication is novel here since the telecommunication systems traditionally used for the control of these vehicles are long-range analog radio communication systems. These systems are useful for the transfer of long-range information between two points (which in this case are the pilot and the aircraft), but present the problem in the poor video quality and the limited variety of file formats allowed for the information they transmit. On the other hand, Wi-Fi connectivity makes it possible to establish totally secure connections, not only point-to-point, but also multiple devices and users can be connected. In addition, they provide sufficient bandwidth for two-way transmission of digital information, allowing even high-definition, real-time video to be transferred. The only drawback of using Wi-Fi-based systems is that their range is considerably more limited than the long-range systems mentioned above. However, this problem can be solved by establishing different access points as repeaters of the Wi-Fi signal. This would allow the vehicle to connect to the point with the strongest signal at all times. In this way, simple studies can be carried out to guarantee connectivity throughout the entire authorized flight territory. Although the signal of Wi-Fi antennas can nowadays reach long distances, the current Spanish legislation does not allow pilots to separate themselves from the UAVs. To connect any UAV to the platform, it is only necessary to install the developed module. This allows connecting to the system's Wi-Fi network and exchange all kinds of data: flight commands, telemetry, route points and associated behavior and HD video. This module is an SBC (Small Board Computer), more specifically a low cost and lightweight Raspberry Pi, based on the Linux operating system connected to a powerful Wi-Fi antenna. This module is in charge of translating the information received from the pilot, the person who is in charge of the security of the system or the platform in the event of automatic flights or changes in behavior due to security (arrest in the case of wanting to access a restricted area).