An Improved PMF-FFT Acquisition Approach Based on Frequency Segmentation for DSSS Signals

With an environment of low signal-to-noise ratio and large frequency deviation, in order to meet the requirement of output signal-to-noise ratio, the acquisition of direct sequence spread spectrum signals (DSSS) requires a long accumulation time, but the existence of large frequency deviation makes the accumulation time have an upper limit. An improved direct sequence spread spectrum signal acquisition approach based on partial matched filter fast Fourier transform (PMF-FFT) is proposed for the low signal-to-noise ratio and large frequency deviation environment. In the acquisition process, we segment frequency search range and apply PMF-FFT approach within each segment. In the traditional PMF-FFT approach, as the signal accumulation time increases, the output significantly reducing, and the received signal cannot be effectively used to accumulate to meet the output signal-to-noise ratio requirement. Different from the traditional approach, the proposed approach reduces the maximum frequency deviation within each segment through the frequency segmentation operation, which can effectively accumulate energy and meet the requirement of DSSS signal acquisition when a low signal-to-noise ratio and a large frequency deviation exist simultaneously.