GNSS Spoofing Mitigation with a Multicorrelator Estimator in the Tightly Coupled INS/GNSS Integration

In recent years, various new portable global navigation satellite system (GNSS) spoofers have emerged that have become an important threat to the integrated inertial navigation system (INS)/GNSS. The spoofing strategies have become increasingly advanced, and the spoofer gradually adjusts the counterfeit signals to covertly take over the target receiver. The existing anti-spoofing algorithms based on INS/GNSS integration show the shortcomings of the reduced detection probability and the inability to mitigate spoofing. In this study, the multipath estimating delay lock loop (MEDLL), originally designed for multipath mitigation, is used in conjunction with INS to suppress the spoofing attacks. First, a bank of correlators is employed to estimate the spoofing and authentic signals. Second, a new spoofing validation and mitigation structure is proposed based on the tightly coupled INS/GNSS integrated system. Finally, the INS-aided reacquisition and spoofing suppression method is derived. The simulated INS measurements were used together with Texas Spoofing Test Battery datasets to evaluate the performance of the proposed anti-spoofing algorithm. The results showed that the spoofing attacks were detected within 1 s and the positioning errors decreased from 600 to 12.9 m. The proposed algorithm can suppress different types of spoofing attacks and ensure reliable positioning and timing results in various complex threat environments.