A Vector-Based GPS Receiver Model for Anti-Spoofing/Jamming in Drone Security

Abstract

Most of unmanned aerial vehicles (UAVs) or drones are GPS navigation based aircraft that rely on civilian GPS signal with lack of authenticity and security. As the results of development in software-defined ratio (SDR) and GPS simulation software, it leads to a huge risk against malicious attacks like spoofing and jamming capabilities. The spoofing attack is potentially significantly more menacing than jamming since the target receiver of UAVs is not aware of this spoofing threat and still providing navigation solution on which seems to be reliable. Therefore, detection and mitigation of interference in general and spoofing/jamming specially has drawn attention from many researchers. My thesis focuses on interference detection by applying integrity check, which is implemented in the tracking loop of software-defined GPS receiver, with the task of continuously monitoring carrier-to-noise density ratio (C/No) of multiple tracking loops. In details, spoofing attacks can be detected if tracking channels’ C/No experience a sudden change below sufficient threshold. A vector-based tracking architecture is employed to mitigation the signal outage during detected interference duration. Both conventional scalar tracking loop (STL) and proposed vector tracking loop (VTL) model are presented and implemented in the software-based GPS receiver. Once a signal outage in the STL is detected based on integrity check results, the mode of tracking is switched to VTL with STL initialization, thus VTL and STL are co-operating assisted each other. Simulations are conducted using a software simulator by SIMULINK that generates digital IF data comparable to a real GPS RF-front end, and resulting digital IF data is processed in signal processing module including acquisition, tracking, navigation data extraction and navigation solutions estimation. The performance of the proposed VTL is evaluated through two type of dataset, namely short and long signal outage of low C/No below 25 db-Hz environment with additional interference of additive white Gaussian noise (AWGN). Experimental results verify that a vector-based tracking loop model can maintain signal lock during signal outage and reduce the effect of interference by improving accuracy of navigation solution based on integrity check results. The experimental results proves that the proposed VDFLL improve performance of navigation solution estimation by 44%.