The theory model establishment and experiment measure of Lidar ranging signal in large incident angle condition

Recently, with the rapid development of unmanned vehicles, When laser radar is used in road graphing of unmanned vehicles, due to the height limitation of the vehicle, the angle between the detection axis of the laser radar and the normal line of the road surface is large, and the probe beam is in a grazing incidence state, which is close to the normal incidence of the conventional laser radar. There is a big difference in detection imaging. This difference has a crucial impact on the rangefinder imaging capabilities of Laser Radar, but to best of the authors’ knowledge, there has not been any papers published studying with this particular working condition. In this paper, we are the first to establish the simulation model of the laser radar ranging signal based on the principle of light transmission delay, and obtains the influence curve of laser oblique incidence, road roughness, and pit package on the laser echo waveform by numerical calculation. Based on this, an experimental system for testing the ranging signal of the laser radar at high angle incidence conditions was established on the prototype of a single-line laser radar, and the laser echo waveforms under different incident angles and road surface conditions were tested. The curves in the numerical analysis have a good consistency, which verifies the correctness of the theoretical model. In addition, it shows that the model we proposed is an effective tool for quantitatively analyzing the influence of pavement characteristics on the laser echo signal under large-angle incident conditions.