LFMCW SAR调频非线性的等效分析方法  

Equivalent Approach to Analyze the Nonlinearity of LFMCW SAR

作　　者：侯海平[1,2] 曲长文[1] 向迎春[1] 苏峰[1] 

机构地区：[1]海军航空工程学院电子信息工程系,山东烟台264001 [2]91039部队北京房,山区102401

出　　处：《电子科技大学学报》2012年第2期198-202,237,共6页Journal of University of Electronic Science and Technology of China

基　　金：“泰山学者”建设工程专项基金;中国博士后科学基金(2005037772)

摘　　要：针对LFMCW的调频非线性问题,结合LFMCW SAR成像系统特性,分析了非线性频率偏移的影响,讨论了选择不同参考信号进行混频情况下的边带效应,提出了一种将非线性频率误差通过相位误差转化为加性噪声的等效分析方法,并通过仿真分析了该等效噪声对LFMCW SAR距离分辨率的影响。结果表明,较低的线性度对差拍频率和信噪比影响很大。该方法可为基于信号处理消除非线性误差的影响提供新的思路。The linearity of linear frequency modulated continuous wave synthetic aperture radar（LFMCW SAR） is an important index to measure the linear frequency modulated（LFM） signal and can cause great effect on imaging quality of SAR.Aiming at nonlinearity of LFMCW and combining the characteristic of LFMCW SAR system,nonlinear frequency error is analyzed and sidebands effects of frequency fixing with different reference signal are discussed.An equivalent approach to transform nonlinear frequency error into addictive noise by virtue of phase errors is proposed and effect of equivalent noise on LFMCW SAR range resolution is analyzed through simulation.Results demonstrate that lower linearity can cause larger effect on beat frequency and signal-to-noise ratio（SNR）.The proposed method can provide new thought for the elimination of nonlinearity influence based on signal processing.

关 键 词：加性噪声 等效分析 线性调频连续波 调频非线性 相位误差合成孔径雷达 

分 类 号：TN957.5[电子电信—信号与信息处理] TN911[电子电信—信息与通信工程]