High Precision Distance Measurement of Micro-Motion Targets Based on FMCW LiDAR

Frequency modulated continuous wave (FMCW) light detection and ranging (LiDAR) is considered as one of the most promising 3D imaging technologies by virtue of its single-photon detection sensitivity, high interference immunity, and high precision. However, due to the micro-motion of the target caused by the environment, a Doppler frequency shift is introduced into the beat frequency signal, which results in measurement inaccuracies. To solve this problem, we propose a dual sweep FMCW LiDAR system and a high precision distance measurement method for micro-motion targets, which can be applied in both active and passive environments. In the former, a 62-fold improvement in range precision could be achieved, and in the latter, the standard deviation of the measurement reached 11 µm.