GPS Signal Acquisition Based on FFT

The acquisition and tracking processes of Global Navigation Satellite System (GNSS) are heavy in the computation load of a GNSS receiver. In order to track and decode the navigation information in the GPS signal, an acquisition algorithm must be used to detect the presence of the satellite signal. Once the signal is acquired, the necessary parameters such as code delay and Doppler shift must be obtained and then the parameters are passed to the tracking program in order to obtain the navigation information. This paper presents the serial search algorithm and the FFT acquisition algorithm based on real GPS IF data. Experiments are finished to compare the performance and computing speed of both the algorithms. As a result, it shows that FFT acquisition algorithm is efficient and further reduces the processing time in signal acquisition process.