Abstract: Spoofing signals, with high elusiveness, are hardly detected by Global Navigation Satellite System (GNSS) receivers, therefore misleading positioning solutions of target receivers and seriously degrading the safety and reliability of GNSS. Current anti-spoofing methods correct the deceived positioning solutions depending heavily on other navigation systems/sensors. To reduce the reliance, this study proposes a new spoofing signal parameter estimation and identification method which estimates time delays and pseudoranges of both authentic and spoofing signals, thereby distinguishing authentic and spoofing ones and computing receiver positions using selected authentic pseudoranges. In this method, the receiver correlation value model with spoofing interference is deeply studied and used in the Extended Kalman Filter (EKF)-based signal tracking loop to estimate the code delays and the signal correlation amplitudes. In the positioning module, pseudorange residuals are employed to detect real and spoofing pseudoranges, and the authentic pseudorange positioning is used to obtain the true position. Simulation results show that the estimation accuracy of the proposed method is 0.1 chip under spoofing attacks with a 0.3-0.9 chip relative delay and a 1-5 spoofing-authentic-signal amplitude ratio. Generally, with the aid of authentic and deceptive signal parameter estimation loops, the proposed method can effectively identify the spoofing signals of each channel, and return the true positioning solution, thus improving the anti-spoofing ability of GNSS receivers.

Key words: GNSS, anti-spoofing technology, tracking loop, Kalman filter, spoofing detection