A Low-Complexity GPS Anti-Spoofing Method Using a Multi-Antenna Array

Spoofing attacks can completely mislead the position solution provided by global navigation satellite systems (GNSS). Recently, several anti-spoofing techniques have been introduced to combat spoofing attacks. However, in most cases the available anti-spoofing techniques are computationally complex or limited to a specific spoofing scenario. This paper provides a low computational complexity approach to mitigate the spoofing signals based on an antenna array processing technique. The proposed method is established based on the fact that all spoofing pseudo random noise (PRN) codes are transmitted from the same source in space. This technique steers a null toward a spatial sector where the maximum spatial energy is coming from. To avoid unintentional attenuation of authentic signals due to the beam pattern profile, the received power of each authentic signal is maximized individually after spoofing mitigation. The proposed anti-spoofing technique provides a low computational complexity process that performs prior to the acquisition stage of GPS receivers. Moreover, this method does not require any antenna array calibration process. Therefore, it can be easily employed as a standalone anti-spoofing module at the receiver input. Simulation results show that the proposed anti-spoofing method performs well for a wide range of received spoofing power. To verify the applicability of this method in real-world scenarios, a real data set has been collected and processed without any outdoor propagation. The data processing results demonstrate the desired performance of the proposed technique for real spoofing scenarios. INTRODUCTION GNSS signals are vulnerable to in–band interference such as jamming and spoofing signals. Spoofing is an intentional interfering signal that aims to coerce GNSS receivers into generating false position/navigation solutions (Humphreys et al 2008). A spoofing attack is more menacing than jamming since the target receiver is not aware of the threat. The rapid advance in software defined radio (SDR) technology has made GNSS spoofing more flexible and less costly; therefore, GNSS spoofers can be made available for civilian misapplications at a low cost. Several anti-spoofing techniques have been proposed in the open literature recently. These methods can be generally divided into two main categories, namely spoofing detection and spoofing mitigation. Spoofing detection algorithms concentrate on discriminating the spoofing attack while spoofing mitigation techniques aim to neutralize the spoofing threat. Most of the previously proposed techniques focus on spoofing detection rather than spoofing mitigation. Amplitude discrimination, time of arrival (TOA) discrimination, consistency cross-check