Range walk error suppression method for PMT-based single-photon lidar using a double-edge discrimination circuit

Photomultiplier tube (PMT)-based single-photon lidars (SPL) hold significant potential for airborne and spaceborne remote sensing. However, under high-flux conditions, the pulse pile-up or dead-time effect causing conventional leading-edge discrimination methods to suffer from severe intensity-dependent range walk errors. This mechanism fundamentally constrains the ranging accuracy in strong-return scenarios. By extracting and processing both the leading- and trailing-edge timing information of the PMT anode pulse, the underestimation and overestimation intensity-dependent range errors are theoretically neutralized. Monte Carlo simulations demonstrate that this dual-edge approach effectively mitigates range walk errors across diverse signal intensities and pulse widths, maintaining high stability regardless of photon flux variations. Furthermore, a custom high-speed dual-edge discrimination module was developed and integrated with a commercial PMT. Experimental results indicate that for the average signal photon number ranging from 0.39 to 19.7 counts, the dual-edge method maintains ranging biases within ±1 cm, effectively decoupling the range walk error from signal intensity. This method provides a robust and hardware-efficient solution for pulse-pile-up compensation, significantly enhancing the ranging accuracy of SPL systems with minimal architectural complexity.