【作者】 吕瑛；

【导师】 刘高辉；

【作者基本信息】 西安理工大学 ， 通信与信息系统， 2009， 硕士

【摘要】 线性调频连续波(LFMCW)雷达是一种通过对连续波进行频率调制来获得距离与速度信息的雷达体制。LFMCW雷达具有无距离盲区、高距离分辨率、低发射功率、结构简单等优点。根据LFMCW雷达的这些特点,利用LFMCW雷达可以更好地解决近距离目标的参数估计问题。随着LFMCW雷达理论、关键技术和应用的迅速发展,近年来LFMCW雷达受到广泛关注。本文首先对LFMCW的发射信号和回波信号进行了建模分析,分析结果表明,为了实现动目标参数估计,对发射信号与回波信号进行混频处理得到差拍信号,再对差拍信号进行相应处理,就可以得到目标参数。其次,本文重点研究了LFMCW雷达实现目标参数估计的方法。本文采用二维FFT算法实现目标距离和径向速度估计；为了提高目标参数估计精度,本文从细化频谱的角度出发,利用Chirp-z变换实现频谱细化；同时还分别对动目标检测、调频带宽、调频周期和二维FFT的点数等问题进行了研究讨论。另外,本文还研究了匀加速运动目标加速度的估计方法,根据LFMCW雷达差拍信号的相位形式,本文采用多项式相位变换算法来实现目标加速度的估计,并对该方法进行了仿真。最后,结合目前产生线性调频信号的常用方法所存在的线性度问题,本文对线性调频信号在非线性时对目标参数估计所产生的影响进行了分析研究,并且对目标径向距离、径向速度和加速度估计算法进行了仿真分析,验证了算法的可行性和正确性。更多还原

【Abstract】 Linear frequency modulation continuous wave (LFMCW) radar is a kind of radar that obtains data on distance or speed by the use of frequency modulation to continuous wave. As the merits of without range blind area, high range resolution and low signal emission power, simple structure etc. Therefore, LFMCW radar may well solute the short range objective’s parameter estimation according to these characteristics. With rapid development of the LFMCW radar theory, the key technologies and the application, the LFMCW radar received the widespread attention in recent yearsA theoretical model has been set up at the beginning of this paper to analyze LFMCW signal. The analysis shows that for obtaining the parameters of moving object, the echoed signal must be processed. The paper presents the analysis and processing of beat signal, which comes from frequency mixing of emission signal and echoed signal, to obtain object parameters.The emphasis of this paper lies in the method of estimation objective’s parameters by LFMCW radar. The Two Dimensional FFT arithmetic was studied for getting data on object’s distance and radial velocity, In order to improve the estimation precision, spectrum refinement has been researched, and a method named Chirp-z arithmetic helps to realize this refinement. Also, the moving target detection, the frequency-modulation band width, the frequency-modulation period and the dot-number of Two Dimensional FFT etc. have been discussed in this paper.Moreover, this article has also studied a way to estimate acceleration of moving object with uniform accelerated velocity. According to the form of phase of LFMCW radar beat signal, this paper uses the multinomial phase transformation algorithm to estimate the goal acceleration, and has carried on the simulation to this method.Finally, considering the problem of linearity in normal method of generating LFMCW, the paper researches the effects took by nonlinearity on object’s parameter-estimation in LFMCW. The arithmetic for estimation of object range, radial velocity and acceleration has also been analyzed and simulated, by which the feasibility as well as correctness of this arithmetic have been confirmed.更多还原