A New Proposed GPS Satellite Signals Acquisition Algorithm Based on the Fast Fourier Transform

摘要

Due to the Doppler Effect caused by the high line-of-sight velocity of satellites and in some cases receivers, the frequency of the Global Positioning System (GPS) satellites signals at the receivers’ level will be transformed into new ones. In the worst case, it can be deviate up to ±10 kHz. The role of the acquisition block in SDR GPS receivers is to detect visible satellites and coarse values of carrier frequency and code phase of each visible one. Several acquisition algorithms are existed now; the first algorithms developed are based on the time domain search. The new generation of GPS receivers is based on the frequency domain calculation. In this context, our developed algorithm is a new approach based on the Fast Fourier Transform (FFT) calculation. Our proposed solution has a fast execution time that can achieve 40% compared with elder ones in addition to its simplicity that make it easier to implement in a FPGA card.