一种适用于相干激光雷达的下变频技术研究

Research on a down conversion technology for coherent lidar

相干激光雷达指的是采用具有相干光源的激光对探测目标发射,并采用激光外差接收,通过后置信号处理来获取目标信息的一种探测方法。本文针对相干激光雷达的回波信号经过光电探测器后输出频率较高、重频周期长、处理数据量大,提出了一种下变频技术来降低频率至零频,并采用梳状滤波器(CIC)和半带滤波器(HB)组成多级采样率转换来实现数据的滤波和抽取。最后通过实验表明,此方法能够在较低数据率下有效地实现高信噪比的采样进行测距。

Coherent laser radar refers to a detection method that uses a laser with a coherent light source to detect the target emission,and uses laser heterodyne reception to obtain target information through post signal processing.In this paper,the echo signal of the coherent laser radar passes through the photodetector,and the output frequency is high,the repetitive frequency period is long,and the processing data is large.A down-conversion technique is proposed to reduce the frequency to zero frequency,and applying the CIC and the HB filter form multi-stage sampling rate conversion to achieve data filtering and extraction.Finally,experiments show that this method can effectively achieve high signal-to-noise ratio samping for ranging at lower date rates.