Pulsed light time-of-flight measurement based on a differential hysteresis timing discrimination method

Abstract

In the pulsed light time-of-flight (ToF) measurement, the timing point generated in the receiver channel is very important to the measurement accuracy. Therefore, a differential hysteresis timing discrimination method is proposed to generate timing points of the receiver channel. This method is based on utilizing the unbalanced characteristics of the fully differential operational amplifier circuit as well as introducing extra hysteresis levels to achieve the stable generation of timing points. With this method, fewer circuit components are consumed and the dynamic range of the receiver channel is not limited by its linear range. The experiments demonstrate that a receiver channel applying the proposed discrimination reaches better single shot accuracy compared to that using leading-edge timing discrimination. This method is also suitable for the timing walk error compensation by means of pulse width. Finally, these results verify the effectiveness of the proposed method in pulsed light ToF measurement.

Distance–Intensity Image Strategy for Pulsed LiDAR Based on the Double-Scale Intensity-Weighted Centroid Algorithm

“…The first kind of method depends on the discriminator and time-to-digital converter (TDC) to determine the time interval between the transmitted pulse and echo pulse. The leading edge discrimination method [8] and constant fraction discriminator (CFD) [9] method are representative. These methods locate the transmitting pulse and echo at a specific moment to form a shaped pulse and then use a TDC to differentiate between them.…”

“…There are two main methods for determining the time difference between LiDAR's transmitted pulse and echo pulse: One relies on a time-to-digital converter (TDC) [8,9]; the other is the full waveform method [10]. The backscattered optical power is internally converted into a voltage, sampled by an analog-to-digital converter, and, finally, transformed into a Digital Number (DN), that is, a scaled integer value called the "intensity" [11].…”

The Short-Range, High-Accuracy Compact Pulsed Laser Ranging System

“…There is no doubt that the timing discrimination error limits the ranging accuracy. For this reason, a differential hysteresis timing discrimination method is reported in detail [ 29 ]. Compared with the traditional leading-edge timing discrimination, this timing discriminator circuit that uses fewer components has better single-shot ranging accuracy.…”