调频非线性的存在影响了线性调频连续波(LFMCW)雷达目标检测能力和距离分辨率。为此,文中提出了一种软件方法实现调频非线性校正的方法。在分析了当前压控振荡器部件的电压频率控制特性基础上,讨论了调频非线性对差频回波信号的影响,将具有调频非线性的雷达目标检测问题转化为差频信号中目标调频分量的检测问题;利用LFM信号在分数阶傅里叶域上呈现出能量聚集这一特性,提出了基于分数阶傅里叶变换的LFMCW雷达多目标检测方法。仿真试验表明,该方法不仅可以有效地改善具有较大调频非线性的LFMCW雷达的目标距离测量精度,同时也提高了多目标的分辨能力。

The chirp non-linearity in linear frequency modulated continuous wave (LFMCW) radar systems causes range resolution and capability of object detection deterioration. A new software method for non-linearity is proposed in this paper. Based on the analysis of the frequency control characteristics of current the VCO components, the affection of non linearity of frequency modulation to the beat frequency echo signal is discussed. The detection of objects in radar which has the non-linearity of frequency modulation can be converted to the detection of the frequency modulation components in beat frequency echo signal. Use the energy aggregation property of fractional fourier transform (FRFT) to LFM signal, the method for multi objects detection based FRFT is presented. The simulation results show that not only the range resolution but the resolution capability of multi-object is largely improved.

国家自然科学基金资助项目