Compact single-photon LiDAR for satellite laser ranging.

Satellite laser ranging (SLR), a cornerstone technology in space geodesy, plays a critical role in satellite orbit determination and Earth gravity field inversion. Here, we developed a compact single-photon LiDAR system for SLR operating at 1550 nm. The system features a bistatic configuration for backscattering noise suppression, an enhanced scan-tracking technique to improve dynamic target detection probability, and an absolute ranging method utilizing chaotic pulse position modulation (CPPM) and the Hough transform. Experimental results demonstrate a static target absolute ranging of 8.56 km, and dynamic ranging capabilities of up to 953.89 km with a ranging RMSE of 0.41 m. The theoretical normal point precision at high pulse repetition frequencies is estimated to be within a few millimeters. Trajectory and full-waveform analysis further validate the system's ability to detect radial velocity (-6.53 ∼ -2.05 km/s ) and attitude changes of targets. This work proves the feasibility of single-photon LiDAR for SLR applications and enables what we believe to be new solutions for satellite orbit determination, space target identification, attitude sensing and debris monitoring.