摘要
线性调频连续波(LFMCW)雷达具有尺寸小、成本低、抗截获等优点,在近距离探测成像中具有独特优势。但LFMCW雷达采用Dechirp接收体制,因此对发射信号的调频线性具有严格要求。而实际系统的非理想线性调频会导致距离压缩结果恶化,影响目标聚焦效果。由于Dechirp后的残余误差的空变性,现有的基于信号处理的补偿方法难以兼顾补偿精度和计算效率。本文首先揭示了匹配滤波和Dechirp处理两种脉冲压缩处理方法之间的理论等效性。然后,基于这种等效原理,提出了一种基于频谱恢复的空变误差补偿方法。新方法通过对Dechirp信号进行预处理,恢复出原始回波信号频谱,再利用匹配滤波方式完成距离压缩处理,可以有效避免误差的空变补偿,实现对非线性调频误差的高效精确补偿。最后,通过仿真数据处理验证了理论分析的正确性和所提方法的有效性。
Linear frequency modulation continuous wave radar has some advantages like small size,low cost,anti-interception and so on,which gives it unique superiority in short-range imaging.However,LFMCW radar adopts Dechirp receiving system,so it strictly requires the frequency modulation linearity of the transmitted signal.In the real systems,the nonlinear frequency modulation will deteriorate the range compression result and affect the focusing effect.Because of the spatial variability of residual error after Dechirp,existing signal processing correction methods are difficult to balance the compensation accuracy and calculation efficiency.This paper first reveals the theoretical equivalence between the matched filtering and Dechirp processing.Then,using this equivalent principle,a space-varying error compensation method based on spectrum restoration is proposed.The new method restored the original echo spectrum by preprocessing the Dechirp signal,and then used the matched filtering for range compression processing,which can effectively avoid the error compensation of the spatial variability and realize the efficient and accurate correction of the nonlinear frequency modulation error.Finally,experimental results demonstrate the correctness of the theoretical analysis and the effectiveness of the proposed method.
作者
刘衍琦
金秋
王跃飞
毛新华
LIU Yanqi;JIN Qiu;WANG Yuefei;MAO Xinhua(Key Laboratory of Radar Imaging and Microwave Photonics,Ministry of Education,College of Electronic and Information Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing,Jiangsu 211106,China)
出处
《信号处理》
CSCD
北大核心
2021年第5期700-711,共12页
Journal of Signal Processing
基金
国家自然科学基金(62071225,61671240)
南京航空航天大学研究生创新基地(实验室)开放基金(kfjj20200409)。
