第20卷
第4期
2012年4月
文章编号
1004924X(2012)04-0888-08
光学精密工程
Optics and Precision Engineering
Vol. 20No. 4
Apr,2012
相位式激光测距谱分析鉴相的无偏改进
王选钢1,2，维宁祎1,2，张珂殊1*
（1中国科学院光电研究院，北京100094;2中国科学院研究生院，北京100049）
摘要：针对相位式激光测距中的鉴相误差，建立了谱分析鉴相的误差模型，提出了在数据预处理中引入希尔伯特变换来距中不容忽略。提出了一种无偏改进方法，通过窗函数法设计正弦信号的简易希尔伯特变换器，将离散傅里叶变换的对象转换为解析信号，在仅增加4次加减法运算和2次移位操作的情况下，实现了近似无偏谱分析鉴相。仿真分析和实验验证结果表明，鉴相均值与真实相位差相同；当信噪比为40dB时，每秒百万次高速鉴相的误差为0.1°；当调制频率为 100MHz时，测距精度达到0.4mm。实验表明，将希尔伯特变换应用于谱分析鉴相，可实现高准确度相位差测量，并可应用于高速相位式激光测距。
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键
词：相位式激光测距；谱分析鉴相；希尔伯特变换；信计偏差
中图分类号：P225.2;TN249
文献标识码：A
doi:10.3788/OPE.20122004.0888
Unbiased improvement of spectrumanalysis phase discrimination forphase-shift laser range finder
WANG Xuan-gang'-, GOU Ning-yil-, ZHANG Ke-shu'
(l.Academyof Opto-electronics,ChineseAcademyof Sciences,Beijing100094,China;
2.GraduateUniversityof Chinese Academy of Sciences,Beijing100049,China)
Corresponding author,E-mail;zhangks@aoe.ac.cn
Abstract: An error model of phase discrinination based on spectral analysis is deduced to reduce the phase discrimination error for a phase-shift laser range finder, and the Hilbert transform is induced to data pre-processing to eliminate the estimation bias of phase difference. The bias and deviation of con ventional spectrum analysis phase discrimination are analyzed. The analysis shows that the bias is in fluenced by initial phases and it can not be ignored in fast and precision measurement. This paper pro-poses an unbiased improvement method. The method uses a window function to design a simple Hil-bert transformer to convert the objective of Discrete Fourier Transform into an analytic signal. Then the nearly unbiased phase difference measurement is achieved by spectral analysis only in increasing four addition and two shift operations. Simulation and experimental results indicate that the mean phase is the same as the real phase difference. When the signal to noise ratio is 40 dB, the measure-ment accuracy for the high speed phase discriminaton is o. 1°. When the modulation frequency is 1o0
收稿日期：2012-01-18；修订日期：2012-02-15
基金项目：国家863高技术研究发展计划资助项目（No.2008AA121304)