A GNSS Spoofing Detection Method Based on the Consistency of Measured and Calculated Carrier Dopplers

Global Navigation Satellite System (GNSS) based positioning, navigation, and time synchronization services have a profound influence on human society. However, the fundamental system is vulnerable due to the low power and the public structure of GNSS signals. The traditional menace for GNSS is jamming which disables the positioning function of receivers. Unlike jamming, spoofing attacks could deviate a victim receiver's reported position away from the authentic one. It is more precarious since the victim is unware of this threat. To detect such spoofing, a consistency check approach of measured and calculated carrier Dopplers is proposed. The measured Dopplers are extracted from carrier tracking loops; the calculated Dopplers are formulated by motion information of the receiver and satellites. The feasibility of the proposed method lies in the fact that the calculated Dopplers would be abnormal compared with the measured Dopplers when a position fix is spoofed away from the authentic one. To put the proposed method into practice and illustrate its performance, a generalized likelihood ratio test (GLRT) based statistical detection model is established in this paper. The simulation results demonstrate the theoretical performance. Moreover, the effectiveness of the developed detection method is validated by a replay spoofing test on a GNSS software-defined receiver. Besides, the spoofing detection performance is improved by a smoothing technique.