GNSS Spoofing Mitigation Based on Code-Carrier Difference Pair Pseudorange Correction

Abstract

Global Navigation Satellite System (GNSS) is vulnerable to spoofing attacks due to its open signal structure. Studying spoofing mitigation methods is, therefore, crucial for ensuring the security of GNSS-based services. However, current spoofing mitigation techniques rely on code-phase estimation of multiple correlators or the assistance of external information, which is costly and lacks practicality. Therefore, we propose a new spoofing mitigation method based on code-carrier difference (CCD) for pseudorange (PR) bias estimation and correction. The method effectively leverages the inherent correlation between carrier and code to construct CCD based on phase, which is then converted into PR bias. This enables effective prediction of PR deviations induced by spoofing. Notably, the technique achieves spoofing mitigation without requiring precise estimation of code-phase offset. The results show that the proposed method can effectively reduce the impact of spoofing signals to around 20 m in scenarios with low power advantage, as well as in static/dynamic and time/positioning spoofing scenarios. In the later stage of spoofing, the proposed algorithm reduces the resolution error by up to 97.0% in all scenarios and maintains a stable and smooth position, velocity, and time (PVT) solution performance throughout the whole time period. The proposed algorithm performs well in terms of mitigation effect, accuracy, robustness, and the smoothness of PVT solution, providing GNSS receivers with an efficient, lightweight, and reliable anti-interference solution.