Low-Complexity Non-Searching Method for First-Order Dynamic DSSS Signal Acquisition

Efficient acquisition of direct sequence spread spectrum (DSSS) signal is crucial under high dynamics and low signal-to-noise ratio (SNR). The current non-search acquisition method based on keystone transform avoids the problem of a sharp increase in computational complexity of the frequency search assisted methods at high dynamic correction accuracy, yet the computational complexity remains high. This paper proposes a low-complexity non-searching first-order dynamic DSSS signal acquisition method, which avoids the calculation of invalid dynamic correction range while ensuring that the frequency offset acquisition range remains unchanged. Specifically, by assuming that the relative delay caused by dynamics remains constant in each data symbol period, and converting the dynamic correction problem into a delay correction problem, the frequency offset acquisition range and the dynamic correction range are decoupled. Then, we analyze the connection between the proposed method and the existing non-search acquisition method Keystone DBZP. Finally, the computational complexity of the proposed method is derived and compared with other methods. Simulation results are provided to illustrate the effectiveness of the proposed method.