# A Software Defined Radio Based Anti-UAV Mobile System with Jamming and Spoofing Capabilities
## 2 Overall System Architecture  
The aim of the system described in this paper is to prevent the intrusion of unauthorized drones, commercial or customized, which includes, for example, land, aerial and water drones operating in restricted areas such as airports, military areas, condomiums, occasional public events or other areas where public safety needs to be guaranteed. Through a touchscreen, the user of the system visualizes a map of the area where he is located, allowing him to select the intended landing spot for an eventual intruder drone. Once an invading drone is detected, the user just needs to point the system at the drone and press the trigger. The system will guide the invading drone to the previously selected site and force it to land. In order to be easily and quickly adapted to the areas to be protected, the system was designed so as to be portable. The modular system incorporates efficient technologies and materials, based on its ease of transportation and handling by defense forces (military and public security). Figure 1 represents the main modules that make up the system. The user module is composed of controls/commands and a user interface and is, thus, responsible for all user inputs. The battery module is responsible for powering the entire system. The processor module consists of the microprocessor, responsible for all system processing. The sensor module is composed of the microcontroller, which is directly connected to the microprocessor and is responsible for managing and collecting data from the whole set of sensors. The transmission module consists of the electronic equipment required for the transmission of radio signals and the directional antennas. The security module protects the system by resorting to authentication through a biometric sensor, which allows operation only to previously authorized users. Several accessories (e.g., telescopic sight, laser optics, bipod, front grip and sling) are incorporated into the system in order to help improve the user experience and, consequently, contribute to the improvement of performance when operating the system for the neutralization of target UAVs. As previously stated, the main functionality of the system is the ability to divert the invading drone to a zone determined to be safe. In order to perform this task, the system needs to acquire the location of the target drone. To determine the location of the invading drone, a set of sensors are attached to the system such as: distance meter, accelerometer, location sensor and magnetometer. In terms of security, to prevent the misuse of the equipment by unauthorized individuals, the system allocates a biometric sensor, as previously stated. Furthermore, through mobile network communications, the system sends a periodic message (time configurable) with the information of the location of the system to a supervising entity. Complementarily, whenever someone initializes the system or initiates the transmission, a message is also sent with the respective username. This system minimizes interference in third party systems through the use of highly directive antennas. In summary, the operation of the system can be divided into five stages, as shown in Figure 2.  
Figure 1: System architecture. The first is the authentication step which is needed for a previously registered user to authenticate himself and to initialize the system, using the security module. The second step is the user input required for defining the zone where the invading drone will land. This is accomplished through the user module. There are two types of jamming implemented in the system: jamming aimed at the communication link between the drone and the remote controller (typically 2.4 GHz) and jamming aimed at the GPS signals received by the drone (around 1.5 GHz). Spoofing of GPS signals is only possible after jamming GPS signals. Therefore, the third step, which corresponds to jamming, comprises two different phases.