# A Software Defined Radio Based Anti-UAV Mobile System with Jamming and Spoofing Capabilities
## 1 Introduction
It was demonstrated that a civil UAV could be \"steered\" by a spoofer by moving its perceived location in the opposite direction of the desired motion. Coarse, short-term control of the UAV was demonstrated in all directions (east, north, and up) during the tests [12]. There have been a few other studies and investigations in the area of GPS spoofing against UAVs. In [11; 13], the authors studied and exploited the vulnerabilities of GPS systems in drones in order to hijack or gain control over the aircrafts. Another example of exploiting GPS vulnerability is that of the UnicormTeam, a group of security researchers focusing on systems based on radio technologies. They proved, in [14], through several approaches, that it is possible to spoof a GPS receiver, which the present authors have also demonstrated in [15]. Some more robust systems have already been developed in order to solve the problem of unauthorized drones. For example, the system presented in [16] is based on the identification of communication protocols for later disruption and/or replication and is designed for implementation in a distributed system. While it may be very effective against a few specific UAVs, the implementation complexity can be very high and the portability may be limited. The systems proposed in [17; 18] also constitute anti-UAV approaches but include only the blocking solution, i.e., they do not have the ability to gain control over the invading drone and force it to land in a safe zone. It is important to note that other, very different, approaches exist. Such is the case of the system presented in [19], which uses a more basic technique, i.e., resorting to a net to capture the invading drone. The system presented in this article uses non-destructive methods, using radio frequency. Motivated by the work above, in this paper, we study a system capable of neutralizing unauthorized UAV flights using low cost SDR platforms. The implemented system is capable of jamming the target UAV while also transmitting false GPS signals so as to block communications, redirect or even gain control of the vehicle flying over protected areas. For evaluating the behavior of the system's operation, several types of jamming techniques were implemented, and different types of GPS receivers were tested as targets for the spoofed signal in different scenarios. Based on our previous work regarding jamming [20]and spoofing [21], and considering, in addition, the problem of determining the location of the target UAV, the goal of this paper is to design and implement a complete mobile system that can, in a controlled way, land the invading UAV in a geographical point determined by the user, thus, neutralizing the potential threat. Differently from other approaches, the system presented in this paper adopts a simpler philosophy being directed to a compact and localized/independent implementation. The main differences between the proposed system and other existing solutions can be summarized as follows:  
* The system presented in this paper does not depend on third-party systems to determine the location of the UAV. * The system presented in this paper does not depend on the detection of specific communication protocols and does not need to carry out any identification of the protocol type used between the UAV and the controller (no sniffing of packages). The system offers a more generalized applicability, since it works for UAVs that use conventional communication schemes and protocols, as well as variations of these. * The proposed scheme does not replicate remote control commands to take over the UAV control. The system acquires indirect control of the UAV by deceiving the radionavigation system and not through signals transmitted by the remote control. Furthermore, the main contributions of this paper can be summarized as follows:
* We propose and describe a low-cost portable system relying on SDR platforms, which can be manipulated simply by a user, and which is capable of detecting and neutralizing unauthorized drones using electromagnetic waves.