Abstract:

According to the requirement of acquisition speed for GPS signals under high dynamic environment, a fast acquisition method applying wavelet transform and improved fast Fourier transform (FFT) is presented. In the baseband preprocessing phase, the sampling signal is processed with discrete wavelet transform, and the approximate signal is used to estimate the code phase and the Doppler frequency shift, which would greatly reduce the baseband data rate. The advantages of the radix2 FFT, radix4 FFT and prime factor algorithm (PFA) are considered comprehensively, and a combination algorithm is put forward to process FFT caused in the signal acquisition phase, which would improve the operational efficiency. The simulation results indicate that the improved method could significantly reduce the acquisition time and enhance the performance of the baseband module.