基于相位补偿的调频连续波大长度测距中的色散校正

Dispersion correction in large-length range finding of frequency modulation continuous wave (FMCW) based on phase compensation

基于调频连续波测距的原理搭建并改进了双光路调频连续波测距系统,在测量光路增加光纤延迟线使测量距离拓展到了65 m.还研究了等光频重采样中色散的影响,推导出了带有色散和光纤延迟线的重采样模型,提出了在调频连续波大长度测距中通过频率幅度来调节相位补偿系数的色散校正方法.实验表明,在45~65 m的范围内增加了光纤延迟线并且有效的校正了色散,校正色散后在65. 165 m处测距值与干涉仪测量值最大误差小于500μm,标准差为246μm,频谱分辨力高达123μm,十分接近理论分辨力.文章的研究为调频连续波大尺寸测量提供了可行性的参考.

In this paper,based on the principle of range finding of FMCW,the range finding system of the double light path FMCW was constructed and improved and the optical fiber delay line was added in the measuring optical path to expand the measuring distance to 65 m.The influence of dispersion in equal optical frequency resampling was also researched and the resampling model with dispersion and optical fiber delay line was deduced in this paper.Therefore,the dispersion correction method that used frequency amplitude to adjust the phase compensation coefficient in large-length range finding of FMCW was proposed.The experiments show that the optical fiber delay line is added within the range of 45~65 m and the dispersion is corrected effectively.After dispersion correction,the maximum error between the range fining at 65.165 m and the measuring value of interferometer is less than 500μm.The standard error is 246μm and the frequency spectrum resolution reaches 123μm,quite close to the theoretical resolution.These results provide feasible reference for the large-length range finding of FMCW.