Two-step GPS interference suppression algorithm for spoofing and jamming

Spoofing and jamming are two kinds of significant interferences in Global Positioning System (GPS). When they coexist in GPS propagation environment, interference suppression becomes more difficult. In the paper, a novel two-step array processing scheme is proposed. Firstly, because conventional power inversion (PI) algorithm can reject jamming effectively, the inverse covariance matrix can be first performed on the signal received by the array to mitigate jamming, considering the nature of inverse covariance matrix. Then, spoofing is suppressed by utilizing the constructed orthogonal projection matrix of spoofing, which is constructed based on spoofing’s steering vector. In the paper, the method utilized the CLEAN method to estimate direction of arrival (DOA) of spoofing according to the period repetitive feature and correlation property of GPS C/A code. The simulation results show that the proposed scheme can reject spoofing and jamming simultaneously, and it is easily realized with small computation amount. Moreover, it can be used as an independent interference mitigation module embedded in the GPS receiver. Simulation results demonstrate the effectiveness of the proposed method.