Carrier tracking method of GPS signals based on sliding DFT and interpolated DFT algorithms

A frequency-domain carrier tracking method of GPS signals is proposed in this article. The sliding discrete Fourier transformation (DFT) algorithm and interpolated DFT algorithm are integrated to estimate carrier frequency according to the analysis of signals in the carrier tracking loop. The range of DFT points is first worked out based on the frequency estimated in the acquisition program. Then, DFT is performed on those points using the sliding DFT algorithm. Finally, carrier frequency is estimated based on the interpolated DFT algorithm and carrier frequency updates in the tracking loop. This method is convenient for application because it requires less computation overhead. Simulation results show that the method can track carrier frequency accurately and the feasibility of the method is validated.