Research On Anti-spoofing Method Of GPS Receiver With Array Antenna

Global positioning system can provide users with accurate three-dimensional position, speed and time information. It is applied in various fields of military and civil. GPS satellite signal is very weak, vulnerable to a variety of intentional or unintentional interference, so the GPS anti-interference problem has been very significant. The intentional interference of GPS can be divided into suppression jamming and spoofing. Anti-spoofing methods of GPS receiver with array antenna is studied in this paper. The contents are as follows:Firstly, the structure of GPS satellite signal, the characteristics of spoofing, and the basic knowledge of spatial adaptive filtering are introduced. Spoofing is very close to the real GPS signal, and the common receiver is difficult to distinguish between them. Spatial adaptive filtering technique has been developed rapidly in recent decades. It provides a new idea for the mitigation of spoofing from the aspects of space.Secondly, performance of the three commonly used methods, such as the Minimum Variance Distortionless Response, Linearly Constrained Minimum Variance, Power Inversion, is analyzed in the presence of GPS spoofing. Depend on the comparison of the signal, spoofing and noise power, characteristic of the eigenvalues of covariance matrix of received signals is summarized. Then, antenna pattern and the output signal to interference and noise ratio of the three methods were analyzed from the theoretical and experimental simulation perspectives.Finally, the improvement measure of MVDR used in the GPS spoofing presence is proposed in the paper. The MVDR algorithm performs well in suppression jamming presence. And the difference of using the MVDR algorithm between suppression jamming and spoofing presence is that the interference to noise ratio is smaller,lead to the gap between the large and small eigenvalues of the received signal covariance matrix is too small. Then, a noise reduction processing is taken to increase the gap improve the conditions of using the MVDR algorithm. Both the theoretical and experimental simulation results show that the new method is effective from the aspect of antenna pattern and the output signal to interference and noise ratio.