Rapid PN Code Acquisition Scheme Based on theCombination of Short Time Correlation and FFT

An algorithm for rapid PN code acquisition based on combined short time correlation and FFT is studied in detail. The correlation time effect and FFT window size effect on the system gain are analyzed in theory when the pre-detection integration time is fixed. A novel method to measure the system performance is proposed in terms of mean system gain and mean detection probability. Also, the principle based on the maximum mean gain criteria is presented for selecting the optimal combination of the FFT size and window size of short time correlation. Simulation shows that even with the Doppler shift, the system performance with the optimal combination approaches the optimal performance without the Doppler shift.