基于欠采样谱分析的激光拍频相位式测距方法

介绍了一种高精度相位式测距方法,载波通过双频氦氖激光器加偏振器产生1.08 GHz光强调制的拍频信号来实现,以克服半导体激光器的调制带宽限制,从而提高测距精度。为降低高速ADC实现难度,根据带通抽样定理,采用欠采样的方法采集波形数据,分析了其理论依据；然后通过全相位谱分析法对采样数据进行鉴相,并重点分析了鉴相数据的截取问题。搭建系统实验,在采样率为50 MSa/s时,157个欠采样数据就能实现0.1 mm左右的测距精度。实验表明,应用欠采样全相位谱分析法,以远低于测尺频率的采样率采样依然能实现高精度测距。

Laser beat-frequency phase-shift ranging based on undersampling spectrum analysis

A high accuracy phase-shift ranging method is introduced.Carrier wave is realized by 1.08 GHz intensity modulation beat frequency signal produced by a dual frequency He-Ne laser and a polarizer,and it overcomes the modulation bandwidth limitation of the semiconductor laser for improving the accuracy of ranging.In order to reduce the difficulty of high speed ADC implement,undersampling method was used to collect waveform data according to the band-pass sampling theory and the theoretical basis was analyzed.The phase-shift of the sampled data was discriminated by all phase spectrum analysis method and the interception problem of phase discrimination data was strictly analyzed.In the system experiment,the accuracy of ranging could be about 0.1 mm when sampling rate was 50 MSa/s and the number of undersampling data was 157.Experiment results show that high accuracy ranging can be realized with the sampling rate far lower than measuring tape frequency when the undersampling all phase spectrum analysis method is used.