Performance Analysis of PN Code Acquisition Using Fast Fourier Transform

A FFT-based parallel acquisition algorithm for direct sequence/spread spectrum radio navigation system is studied to solve long PN code acquisition using serial method. Frequency domain analysis of FFT to acquire signal is applied in this paper and state transfer function is used to derive the expression of average acquisition time. Theoretical analysis shows that FFTbased acquisition algorithm can efficiently solve the correlation peak fade caused by the Doppler shift in high dynamic receiving and transform two-dimension search of the code phase and frequency in one acquisition period, thus resolving the fast acquisition for PN code in high dynamic situation. The results shows that the acquisition time is shortened up to one order in high SNR compared with serial acquisition method.