基于插值短时分数阶傅里叶变换-变权拟合的线性调频信号参数估计  

Parameter Estimation of Linear Frequency Modulation Signal Based on Interpolated Short-time Fractional Fourier Transform and Variable Weight Least Square Fitting

作　　者：曹伟浩 姚直象[1] 夏文杰 闫肃 CAO Weihao;YAO Zhixiang;XIA Wenjie;YAN Su(School of Electronic Engineering,Naval University of Engineering,Wuhan 430033,Hubei,China;Zhangzhou Base Preparation Office of National Ocean Technology Center,Xiamen 361000,Fujian,China;Unit 91388 of PLA,Zhanjiang 524000,Guangdong,China)

机构地区：[1]海军工程大学电子工程学院,湖北武汉430033 [2]国家海洋技术中心漳州基地筹建办公室,福建厦门361000 [3]91388部队,广东湛江524000

出　　处：《兵工学报》2020年第1期86-94,共9页Acta Armamentarii

基　　金：国家自然科学基金项目(51679247)

摘　　要：针对低信噪比下线性调频(LFM)信号参数估计精度不高的问题,提出一种基于Rife插值短时分数阶傅里叶变换(STFRFT)-变权拟合(VWSF)方法。该方法利用STFRFT提高LFM信号的聚集性,实现对LFM信号瞬时频率的高精度估计,并通过VWSF进一步提高信号初始频率和调频率的估计精度。推导得到了初始频率和调频率估计的克拉美-罗限(CRLB),分析了信号时长、滑窗次数等因素对CRLB的影响。仿真实验及海试结果表明,相比于传统基于短时傅里叶变换的估计方法,Rife插值STFRFT-VWSF方法具有更高的LFM信号参数估计精度。A Rife interpolation short-time fractional Fourier transform(STFRFT)-variable weight least square fitting(VWSF)algorithm is proposed for solving the problem of low parameter estimation accuracy of linear frequency modulation(LFM)signal under low signal-to-noise ratio(SNR).STFRFT is used to improve the aggregation of LFM signals,and the estimation accuracy of instantaneous frequency of signal is improved by VWSF,thus estimating the instantaneous frequency,initial frequency and modulation frequency of LFM signal.The Cramer-Rao lower bound(CRLB)of the signal parameters estimation is derived,and the factors affecting the estimated parameter CRLB and the variation of CRLB with it are analyzed.The simulated results show that the Rife interpolation STFRFT-VWSF algorithm has better estimation accuracy of LFM signal parameters,the parameter estimation and CRLB theoretical analysis are rational,and the feasibility of the algorithm is proven through sea test.

关 键 词：线性调频信号 参数估计 短时分数阶傅里叶变换 变权拟合 Rife插值 克拉美-罗限 

分 类 号：TN911.72[电子电信—通信与信息系统]