调频连续波干涉技术对运动目标实时测距时,引起的多普勒效应会导致测量结果存在偏差。针对此问题,提出对激光光源的光学频率进行三角波调制的方法。在一个调制周期内产生两个调频方向相反的频率扫描信号,利用多普勒效应在两个调频方向上的频移量互为相反,可消除多普勒影响。实验结果表明:基于频率为2 Hz、幅度为15.57 μm的单方向运动,三角波调制能够克服多普勒频移产生的5 mm测量偏差,目标距离测量结果标准差达0.035 mm;实现800 mm测量范围内,速度为1 mm/s的运动目标距离测量,具有良好的线性度;在800 mm处实现的测量速度最大可达9 mm/s,最小相对误差可达0.067%。该方法可实现运动目标距离的实时跟踪测量,有利于调频连续波干涉测距技术的广泛应用。

When a frequency-modulated continuous-wave interference technique is used to measure the distance to a moving target in real time, the Doppler effect causes deviations in the measurement results. To solve this problem, we propose a method that employs triangular wave modulation on the optical frequency of the laser light source. By generating two frequency-swept signals with opposite frequency-modulation directions in one modulation period, the Doppler effect can be eliminated using the opposite frequency shifts between the two frequency-modulation directions. Experimental results show that triangular wave modulation at a frequency of 2 Hz and an amplitude of 15.57 μm can overcome a 5-mm measurement deviation caused by the Doppler shift for single-direction motion; the standard deviation of the target distance measurement results is 0.035 mm. Simultaneously, we realize a distance measurement for a target moving with a velocity of 1 mm/s over a measurement range of 800 mm with good linearity. This technique also achieves a speed measurement of up to 9 mm/s at 800 mm, and the minimum relative error can reach 0.067%. The method can be used for real-time tracking measurement of the distance to the moving target, and it is useful for a wide range of applications of frequency-modulated continuous-wave interference-ranging technology.