基于分数阶Fourier变换的微弱LFM信号检测

Detection of Weak LFM Signal Based on the Fractional Fourier Transform

摘要:

为了提高侦察系统对微弱 LFM信号的检测能力,文章提出了一种基于分数阶 Fourier变换的微弱 LFM的检测方法。首先,分析 LFM信号在离散分数阶 Fourier变换计算条件下的输出信噪比,得出当观测信号的采样点数增大时,分数阶 Fourier变换可有效改善输出信噪比。利用该结论,提出了通过提高信号的采样频率或者对已采样信号作插值的方法,改善分数阶 Fourier变换对微弱 LFM信号的检测。最后,仿真验证该方法是有效的。

Abstract:

In order to improve the detection ability of reconnaissance system for weak LFM signal, a method of detection ofweak LFM signal was presented based on the fractional Fourier transform. First, the output SNR of LFM signal was ana.lyzed based on digital computation of the fractional Fourier transform. It was discovered that the fractional Fourier trans.form could improve the output SNR of LFM signal when signal’s sampling points were added. Using this conclusion, the method was presented by adding or interpolating signal’s sampling points, to improve detection ability of the fractionalFourier transform for weak LFM signal. Finally, the effectiveness of the method was verify by simulations.