脉冲噪声下基于NAT函数的LFM信号多径时延估计  

Multipath time delay estimation method of LFM signals based on NAT function in impulsive noise

作　　者：陈梦 行鸿彦[1,2] 王海峰[1,2] Chen Meng;Xing Hongyan;Wang Haifeng(Jiangsu Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters,Nanjing University of Information Science&Technology,Nanjing 210044,China;Jiangsu Key Laboratory of Meteorological Detection and Information Processing,Nanjing 210044,China)

机构地区：[1]南京信息工程大学江苏省气象灾害预报预警与评估协同创新中心,南京210044 [2]南京信息工程大学江苏省气象探测与信息处理重点实验室,南京210044

出　　处：《电子测量与仪器学报》2022年第7期73-81,共9页Journal of Electronic Measurement and Instrumentation

基　　金：国家重点研发计划(2021YFE0105500);国家自然科学基金(62171228)项目资助。

摘　　要：针对脉冲噪声环境下无法准确估计线性调频(LFM)信号多径时延的问题,分析非线性幅值变换法抑制脉冲噪声的原理,设计了一种新的非线性幅值变换函数P-NAT(piecewise-NAT)函数,证明了任意随机变量经该函数变换后存在有限二阶矩,提出了基于P-NAT函数的LFM信号多径时延估计方法。分别对发射信号和P-NAT函数变换后的含噪多径接收信号进行最佳阶次FRFT,根据FRFT域的峰值位置偏移量和时延的关系,实现LFM信号的多径时延估计。仿真结果表明,该方法在广义信噪比为0 dB、噪声特征指数大于0.2的情况下,时延估计归一化均方根误差小于10^(-4),适用于低信噪比和强脉冲噪声环境下的LFM信号多径时延估计。In order to solve the problem that it is difficult to accurately estimate the multipath time delay of linear frequency modulation(LFM)signals in impulse noise environment,this paper designs a new nonlinear amplitude transformation function P-NAT(piecewise-NAT)function,and proves that any random variable has finite second-order moment after transformation by this function,a multipath time delay estimation method of LFM signals based on P-NAT function is then proposed.The optimal order FRFT is performed on the transmitted signal and the noisy multipath received signal transformed by P-NAT function respectively.According to the relationship between peak position offset in FRFT domain and the time delay,the multipath time delay estimation of the LFM signal is realized.Simulation results show that this method is superior to fractional lower order statistics method and myriad filter method in impulse noise suppression,when the generalized signal-to-noise ratio is 0 dB,the normalized root mean square error of time delay estimation is less than 10^(-4).It is suitable for multipath time delay estimation of LFM signals in low signal-to-noise ratio and strong impulse noise environment.

关 键 词：多径时延估计 非线性幅值变换 Α稳定分布 分数阶傅里叶变换 

分 类 号：TN911.7[电子电信—通信与信息系统]