Fast Signal Acquisition Algorithm Based on Doppler Frequency Hierarchical Search Strategy

The size of Doppler frequency search interval is crucial for determining the acquisition time of Direct Sequence Spread Spectrum (DSSS) signals. The existing acquisition algorithms cannot adapt to the wide range of carrier-to-noise ratio changes when determining the Doppler frequency search interval, which leads to the waste of acquisition time. This study proposes a fast signal acquisition algorithm based on Doppler frequency hierarchical search. A hierarchical search strategy is used to traverse the Doppler frequency uncertainty space with different intervals at different levels. The signals with different carrier-to-noise ratio can be quickly captured through Doppler layer by layer search, Doppler search interval adjustment, and interlayer Doppler search frequency multiplexing. The simulation results indicate that compared with the signal acquisition algorithm with fixed Doppler search interval, the proposed algorithm can significantly reduce the average number of search frequency points and improve the acquisition speed.