基于ZFFT的低信噪比无人机信号载频估计方法

摘要

Based on the Zoom-FFT and quadratic interpolation (or Rife algorithm), a fast and accurate carrier frequency estimation method for UAV signal under low SNR conditions is proposed. This method utilizes FFT to get the coarse estimation of the carrier frequency, and then zooms the spectrum through the improved ZFFT, which simplifies the FIR filter and achieves filtering and decimation simultaneously by using an integrator. Finally, the quadratic interpolation method (or Rife algorithm) is employed to further improve the accuracy of frequency estimation. The simulation results show that the proposed method can accurately estimate the carrier frequency of UAV signal in real-time , even under low SNR conditions.%针对远距离探测民用微型无人机信号时的低信噪比条件下高精度载波频率估计问题,提出基于Zoom-FFT(ZFFT)和二次插值(或Rife算法)的快速、精确估计改进算法.算法先利用FFT粗估信号频率,然后利用ZFFT算法对频谱细化,通过简化数字滤波器,采用积分求和的方式滤波,并与数据抽取相结合,同时实现滤波与抽取.最后,利用二次插值法(或Rife算法)对载频估计值作进一步修正.仿真结果表明,所提算法在低信噪比条件下估计精度和运算效率均有明显优势.