Anti-Spoofing Performance Assessment of the Vector Tracking Loop in Challenging Environments

Under harsh propagation conditions, Global Navigation Satellite Systems (GNSS) receivers are susceptible to signal degradation, which can lead to loss of signal lock. Unlocked receivers, when subjected to spoofing attacks, are highly susceptible to false re-acquisition, and their tracking-stage anti-spoofing algorithms may become ineffective, thereby simplifying the execution of spoofing interference. Compared to the traditional scalar tracking loop (STL), the vector tracking loop (VTL) demonstrates superior performance in maintaining Positioning, Navigation, and Timing (PNT) service continuity in complex environments. Therefore, this study designs an enhanced VTL by developing an adaptive loop controller and constructs a composite interference scenario using the Oak Ridge Spoofing and Interference Test Battery (OAKBAT) database to compare the anti-spoofing performance of STL and VTL under various application challenges. In the os2 scenario, the STL’s root mean square (RMS) value of the receiver clock error increases sharply to 601.1 m owing to the re-acquisition, while the VTL is not affected by the signal interruption. In the os4 scenario, the RMS value of its position solution deviation was reduced by 66.35% and 80.83% compared with that of the STL before and after signal interruption, respectively. The study demonstrates that VTL, empowered by an Extended Kalman Filter (EKF) and interchannel cooperation, possesses significant anti-spoofing advantages in adverse environments. These findings highlight the significant advantages of VTL in improving the endogenous security of GNSS receivers and provide key insights for designing anti-spoofing algorithms for challenging environments.