A fast acquisition algorithm of GNSS receiver based on SFFT

Abstract

Acquisition and reacquisition relate to GNSS receiver performance directly. In many environments we need faster acquisition. So we design a sparse fast Fourier transform algorithm that can be used in satellite signal receiver. This algorithm mainly includes three steps. To begin with, we use window function to filter signal. Moreover, we hash Fourier coefficients to different “frequency bucket”. Perform location and valuation estimating at last. Using this algorithm we can calculate k maximum Fourier coefficients quickly. This algorithm has simple structure and run time is sub-linear compared with signal length. According to the characteristic we designed an acquisition method using SFFT to replace normal FFT. Finally, simulation result shows that the algorithm can substantially reduce complex computation under normal signal noise ratio.