A time-frequency domain approach for global navigation satellite systems (GNSS) is proposed to detect various types of chirp interference. In order to estimate the frequency of interference, a model based nonlinear fitting algorithm is used in this paper and it is based on a Kalman filtering approach to short-Time Fourier analysis. The performance of the interference frequency tracking algorithm is evaluated for scenarios of GPS signal in the presence of a chirp type interference. By analyzing the results, the proposed algorithm can track the interference when the jammer to signal ratio (J/S) of GNSS interference signal is more than 30dB, which seriously affects the accuracy of the GNSS.

Keywords: chirp frequency tracking algorithm, GNSS interference, nonlinear fitting algorithm, fourier series modeling