Theoretical detection model of SiPM-based photon-counting lidars and performance analysis under different discrimination thresholds.

Recent advancements in single-photon detectors have made photon-counting lidar a highly attractive technology for remote sensing, providing unparalleled detection performance and ranging accuracy under extremely weak-signal conditions. The silicon photomultiplier (SiPM), also known as the multi-pixel photon counter (MPPC), is composed of arrays of Geiger-mode avalanche photodiodes (Gm-APDs). It has the advantages of an extended dynamic range, a compact form factor, cost-effectiveness, and ease of integration. However, the multi-pixel, single-channel characteristic of SiPM gives rise to substantial pulse pile-up effects in its voltage output, which significantly impact detecion performance and is not adequately described by existing models. This study proposes a theoretical detection model for SiPM-based photon-counting lidar under different discrimination thresholds considering the pulse pile-up effect. Monte Carlo simulations are further utilized to model the range walk error (RWE) and ranging uncertainty of SiPM-based lidars. A photon-counting SiPM-based lidar is built to verify the proposed method, and the experiments are conducted at four different signal levels over a range of discrimination thresholds. The theoretical and experimental detection probabilities agree well (R-square of 0.98), and the range walk errors also have good agreement (R-square of 0.92 and RMSE of 2.7 cm). Finally, we optimize the discrimination threshold from the perspectives of geometry and radiation, providing comprehensive guidance for system design and data applications, which is of great significance for future spaceborne photon-counting lidars.