LFMCW雷达单目标参数估计方法的研究
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。
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 years
A 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.
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。
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 years
A 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.
引文
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[2]M. I. Skolnik. Radar handbook[M], Second Edition. New York,1990.
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[9]凌太兵.LFMCW雷达运动目标检测与距离速度去耦合[D].成都：电子科技大学,2003.
[10]张容权,杨建宇,熊金涛.基于多项式相位变换的线性FMCW雷达目标加速度和速度估计方法[J].电子学报,2005,33(3)：452-455.
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[21]钱云襄,刘渝,黄慧慧.线性调频连续波信号参数估计算法[J].现代雷达,2006,28(3)：40-43.
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[33]陆必应,梁甸农.调频线性度对线性调频信号性能影响分析[J].系统工程与电子技术,2005,27(8)：1384-1386.
[34]胡翔,王东进.一种提高LFMCW雷达调频线性度的新思路[J].中国科学技术大学学报,2001,31(1)：63-67.
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[42]Rongquan Zhang, Yulin Huang, Jianyu Yang, Jintao Xiong. Improving Range Precision of LFMCW Radar Based on Frequency Domain Up-Sampling-Interpolating Method[J]. IEEE conference proceeding,2005,(2):777-780.
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[2]M. I. Skolnik. Radar handbook[M], Second Edition. New York,1990.
[3]丁鹭飞,耿富录.雷达原理(第三版)[M].西安：西安电子科技大学出版社,2002.
[4]G.Stove. Linear FMCW radar technique[J]. IEE Proceedings-F (Radar and Signal Processing), 1992,139(5):343-350.
[5]刘国岁.连续波雷达及其信号处理技术[J].现代雷达,1995,17(6)：20-36.
[6]D. C. Schleher. Low probability of intercept radar[C]. Proc. IEEE International Radar Conference, 1985, (10):346-349.
[7]林茂庸,柯有安.雷达信号理论[M].北京：国防工业出版社,1984.
[8]杨建宇,凌太兵,贺峻.LFMCW雷达运动目标检测与距离速度去耦合[J].电子与信息学报,2004,26(2)：169-173.
[9]凌太兵.LFMCW雷达运动目标检测与距离速度去耦合[D].成都：电子科技大学,2003.
[10]张容权,杨建宇,熊金涛.基于多项式相位变换的线性FMCW雷达目标加速度和速度估计方法[J].电子学报,2005,33(3)：452-455.
[11]Rongquan Zhang, Yulin Huang, Jianyu Yang. LFMCW Radar Multi-target Acceleration and Velocity Estimation Method[J]. ICSP'04 Proceedings,2004:1988-1991.
[12]肖汉,杨建宇,熊金涛.LFMCW雷达多目标的MTD-速度配对法[J].电波科学学报,2000,20(6):34-38.
[13]史林,张琳.调频连续波雷达频谱配对信号处理方法[J].西安电子科技大学学报,2003,30(4)：45-47.
[14]张明友,汪学刚.雷达系统[M].北京：电子工业出版社,2006.
[15]刘庆云,李志舜,李海英.多分量多项式相位信号的参量估计[J].电子学报,2004,32(12)：2031-2034.
[16]王小谟,张光义.雷达与探测[M].北京：国防工业出版社,2008.
[17]王月鹏,赵国庆.二维FFT算法在LFMCW雷达信号处理中的应用及其性能分析[J].电子科技,2005,(5)：25-28.
[18]董晖,姜秋喜,毕大平.二维FFT在TM320系列DSP中的实现[J].雷达与对抗,2000,(1)：34-38.
[19]杜川华,龚耀寰.LFMCW雷达的距离／多普勒处理[J].电子科技大学学报,2004,33(1)：27-30.
[20]周刚,苏保平,傅佑麟.LFMCW雷达数字化测距测速的工作参数设计[J].电光与控制,2007,14(3)：29-31.
[21]钱云襄,刘渝,黄慧慧.线性调频连续波信号参数估计算法[J].现代雷达,2006,28(3)：40-43.
[22]宋长哲.LFMCW雷达多目标检测算法研究[D].西安：西安电子科技大学,2007.
[23]陈祝明,丁义元,向敬成.采用Chirp-z变换提高LFMCW雷达的测距离精度[J].信号处理,2002,18(2)：110-112.
[24]王春艳,黄仁欣,宗成阁,钱月.基于Chirp-z变换的LFMCW系统测距算法仿真研究[J].微计算机信息,2005,21(3)：188-192.
[25]宋玮.FMCW雷达测距精度及其信号处理技术的研究[D].南京：南京理工大学,2004.
[26]刘宝,刘军民.FMCW雷达快速高精度测距算法[J].电子测量与仪器学报,2001,15(3)：41-45.
[27]陈祝明,丁义元,向敬成.提高线性调频连续波雷达测距精度的最大值估值算法[J].系统工程与电子技术,1999,21(6)：39-42.
[28]汪学刚,袁湘辉,向敬成,冯建雄.调频线性度与零差拍线性调频连续波雷达的距离分辨力[J].系统工程与电子技术,1997,(10)：19-23.
[29]程佩青.数字信号处理教程[M].北京：清华大学出版社,2001.
[30]贾兴泉.连续波雷达数据处理[M].北京：国防工业出版社,2005.
[31]李保国,王远模,赵宏钟,付强.调频线性度对chirp信号的距离分辨力影响仿真分析[J].系统仿真学报,2005,17(4)：986-989.
[32]张立志,汪学刚,向敬成.调频线性度与FMCW雷达距离分辨力的关系[J].信号处理,1999,(15)：93-97.
[33]陆必应,梁甸农.调频线性度对线性调频信号性能影响分析[J].系统工程与电子技术,2005,27(8)：1384-1386.
[34]胡翔,王东进.一种提高LFMCW雷达调频线性度的新思路[J].中国科学技术大学学报,2001,31(1)：63-67.
[35]陈祝明,丁义元,向敬成.扫频非线性对线性调频连续波雷达测距精度和距离分辨力的影响[J].电子学报,1999,27(9)：103-104.
[36]孙仲康.雷达数据数字处理[M].北京：国防工业出版社,1983.
[37]A.W.里海捷克.雷达分辨理论[M].北京：科学出版社,1973.
[38]孙屹,李妍.MATLAB通信仿真开发手册[M].北京：国防工业出版社,2005.
[39]Shimon Peleg, Benjamin Friediander. The Discrete Polynomial-Phase Transform[J]. IEEE Transactions on Signal Processing.1995,43(8):1901-1914.
[40]周良臣.多项式相位信号的检测与参数估计[D].成都：电子科技大学,2006.
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