基于Pei采样型DFRFT算法,提出了一种线性调频脉冲压缩新方法。该方法通过补零延拓从而将线性调频脉冲的时延估计问题转化为中心频率估计问题,再利用分数阶傅里叶变换对线性调频信号的能量聚集性实现与传统线性调频脉冲压缩性能相近的效果。在此基础上,导出了其离散距离估计式的解析表达,并分析了其离散精度以及多普勒频移的影响。该方法具有较强的抗多普勒频移能力,并在保证测距精度条件下大大降低了运算量。仿真结果证明了理论推导的正确性。
Based on Pei sampling-type DFRFT algorithm, a novel method of linear frequency-modulated pulse compression is proposed. Through zero padding and prolongation, the time delay estimation of linear frequency-modulated (LFM) pulse is transformed into the center frequency estimation. In this way, the result approximate to the conventional LFM pulse compression can be obtained by utilizing the LFM pulse energy concentration of fractional Fourier transform. The analytic expression of discrete range-finding estimator is derived and the corresponding dispersion accuracy and the influence of Doppler shift are analyzed. It is found that the proposed method has strong robustness on Doppler shift, and reduces the computation complexity by half without the decline of range-finding accuracy. The simulations prove the above-mentioned theories.