Long-distance dual-comb ranging in real-time with an update rate of 7.7-kHz using a free-running laser

We demonstrate a system based on dual-comb LiDAR that can measure absolute distances at a high update rate of 7.7 kHz in real-time. This is enabled by a novel LiDAR frontend combined with a GPU-accelerated algorithm, which allows for real-time reconstruction of the target's position. We track the movements of a retroreflector attached to a trolley on a comparator bench at distances of around 35 m and 50 m for 10 s. Comparing the relative measurements to a reference Doppler interferometer, we find that we can track the target's motion with micrometer-level residual errors, even over these long distances.