Research On Improving The Accuracy Of Pulsed Laser Ranging Based On Vortex Beam Modulation

Pulsed laser ranging is a ranging method that uses laser as the detection light source and the signal working mode is pulse signal.Because of its good real-time performance,easy-to-build ranging system,and long detection range,it is widely used in military target ranging,satellite ranging,vehicle driving ranging and other fields.In order to improve the signal-to-noise ratio and ranging accuracy of the pulsed laser ranging system,this article improves the pulsed laser ranging system by replacing the detection light source with a vortex beam,and adds a noise filter system at the receiving end of the ranging system to control the signal,in order to improve the signal-to-noise ratio and ranging accuracy of the pulsed laser ranging system.This paper replaces the light source in the pulsed laser ranging system with a vortex beam,and simulates the lateral spatial light field distribution of vortex beams with different topological charges by analyzing the light field equation of the vortex beam.The topological charge of the vortex beam observes the characteristics of the lateral spatial light field distribution of the vortex beam.The background noise of Gaussian distribution is superimposed on the vortex beam signal for subsequent simulation of transmission and noise filtering.When the topological charge of the vortex beam is not zero,the spatial distribution of the transverse light field is a circular ring,and as the topological charge increases,the radius of the circular ring also increases.Under the interference of background noise,the spatial distribution of the lateral light field of the echo signal still has a ring structure.The generalized Huygens-Fresnel principle is used as the basic theory for studying the propagation of vortex beams in free space,and the Kolmogorov turbulence model is selected as the atmospheric turbulence model,and appropriate turbulence parameters are selected.The random phase screen method is used to simulate the transmission process of the vortex beam,and the spatial distribution of the transverse optical field of the echo signal is obtained.The vortex beam is distorted under the influence of atmospheric turbulence.Different noise filtering parameters are selected to filter the echo signal.The signal-to-noise ratio under different noise filtering parameters is calculated,and the ranging accuracy of the ranging system is calculated by Monte Carlo algorithm.The effect of improving signal-to-noise ratio and ranging accuracy is related to filtering parameters.Finally,the experimental research of pulsed laser ranging system based on vortex beam modulation is carried out.The experiment researched the modulation efficiency of the transmitted signal,and processed the signal under different noise filtering parameters,realized the separation of signal and noise,and finally realized highprecision ranging.