Interference Suppressing and Null Broadening Method for GNSS Receiver Based on Circular Antenna Array

How to improve the performance of Global Navigation Satellite System (GNSS) receiver in purposive interferences and complex electromagnetic environment is a challenge topic. Moreover, the small angle offset in interference direction, which is caused by high-speed relative motion between jammer and receiver makes big trouble for anti-jammering processing. Although some null broadening technics have been proposed to deal with this situation, they all aim at linear array, which is not applicable for practical situation. This paper introduces Generalized Sidelobe Canceller (GSLC) configuration, which is insensitive to array imperfections, and Adaptive Digital Beamforming (ADBF) algorism in circular array to suppress interferences, and formulates the null broadening model in circular condition by correcting covariance matrix, which solve the problem of interference directions mismatch. Simulation results demonstrate that the proposed method could suppress as many interferences as the theoretical maximum and null can be broadened significantly by correcting covariance matrix.