基于TSLPFT^1-FFT的线性调频信号参数估计方法  

Parameters estimation of linear frequency modulation signal based on TSLPFT^1-FFT

作　　者：孙志国[1] 陈晶[1] 申丽然[2] 郭黎利[1] 

机构地区：[1]哈尔滨工程大学信息与通信工程学院,黑龙江哈尔滨150001 [2]大连海事大学信息科学技术学院,辽宁大连116026

出　　处：《电路与系统学报》2011年第5期24-29,共6页Journal of Circuits and Systems

基　　金：国防863创新基金项目(2010AAJ209);国家自然科学基金资助项目(60803087);黑龙江省自然科学基金(F201040)

摘　　要：线性调频信号(Liner Frequency Modulation,LFM)广泛应用于雷达、通信、地震勘测等领域,为了解决传统方法对其调频率和中心频率参数估计性能较差的问题,提出了基于一阶局部多项式傅里叶变换两级搜索(Two-step Search one-order Local Polynomial Fourier Transform,TSLPFT1)和快速傅里叶变换(Fast Fourier Transform,FFT)的LFM信号参数估计方法。该方法利用LFM信号的一阶LPFT能量峰值特性估计调频率,再利用单频信号FFT的冲激特性来估计中心频率。首先,采用LPFT1粗搜索得到调频率的粗估计值,再利用LPFT1精搜索实现调频率的精确估计,然后根据估计参数对信号解线调,最后进行FFT峰值检测得到中心频率估计值。理论分析和仿真结果表明:与基于LPP-Hough变换或FRFT的参数估计方法相比,在信噪比大于0dB时本方法具有更高的估计精度,同时能够在较低信噪比下实现多分量LFM信号参数的有效估计。Linear Frequency Modulation（LFM） signal is widely applied in fields such as radar,communication,earthquake exploring,etc.To solve complexity and accuracy problems in traditional methods,a parameters estimation method of LFM signal based on Two-step Search one-order Local Polynomial Fourier Transform（TSLPFT1） and Fast Fourier Transform（FFT） is proposed.It uses energy-concentrated property of LFM signal by one-order LPFT to estimate frequency modulate rate and Dirac impulse property of single frequency signal by FFT to estimate center frequency.First one-order LPFT is performed on LFM signal to obtain the rough estimation of frequency modulate rate,then compute it again to get exact value that uses to dechirp signal,last perform FFT with peak-detection to estimate center frequency.Performance analysis and simulation results show that it has better precision of parameters estimation compared with methods based on LPP-Hough transform and FRFT when SNR is higher than 0 dB,and it is also an effective method to estimate parameters of multi-component LFM signals.

关 键 词：一阶局部多项式傅里叶变换两级搜索 线性调频 两级搜索 参数估计 

分 类 号：TN911[电子电信—通信与信息系统]