Full Waveform Recovery Method of Moving Target for Photon Counting Lidar

Photon counting lidar has emerged as a strong candidate technology for active detection applications because of its advantages of single photon sensitivity and high-ranging accuracy. The timing histogram of a single pixel for photon counting lidar contains the target's range information, while the laser echo of full-waveform lidar contains abundant structure and reflection information of the target. Based on the previous work of full waveform correction for stationary targets, we propose a new method of full waveform recovery for moving targets, aiming at the issue of obtaining the characteristics of ultra-long-range moving targets under high-flux conditions. Our method achieves full-waveform recovery by means of data preprocessing, motion compensation, and photon waveform correction. Through simulation calculations, we analyze and compare the effectiveness of each step of the method. Compared with the raw histogram, the normalized root mean square error (NRMSE) of the recovery full waveform and the ideal waveform is reduced from 0.137 to 0.032. Furthermore, we validate the algorithm's robustness. As the speed increases from 5 to 340 m/s, the NRMSE is always less than 0.04. The results indicate that the recovery waveform of targets hardly varies with changes in velocity. For an accumulation of 200 pulses, when the signal photons are 0.019-3 and the signal-to-noise ratio is below 0.033, the algorithm consistently exhibits excellent performance. Besides, we have demonstrated that for single-layer moving targets, multilayer moving targets, and round-trip moving targets, the algorithm has good performance on the recovery of the targets' full-waveform, and the NRMSE is less than 0.0054. This provides a new idea for obtaining the shape of targets with variable speeds at a single pixel and provides exciting news for applications such as the detection and recognition of ultra-long-range aerial targets and the detection of space debris.