Research On Radio Propagation Prediction Method Based On Google Earth And Lidar Point Cloud

With the rapid development of the information society,the mobile communication technology with electromagnetic wave as the carrier of information has been more and more widely used in various fields,such as aerospace,Internet of things,remote control and telemetry,intelligent transportation and other fields.In the actual geographic environment,due to the existence of uneven terrain,diversified surface cover medium,complex and changeable atmospheric structure,the effects of path loss,shadow fading and multipath propagation are caused by radio waves,which have caused some difficulties in the prediction of the wave propagation.This paper studies the prediction model of wave propagation in three-dimensional geographic environment,constructs a real wave propagation environment,and simulates and analyzes the distribution of electromagnetic situation in the scene.It can provide some reference for the location optimization of the base station,the configuration of network radio and so on.The Parabolic Equation(PE)model is a deterministic wave propagation prediction model derived from the wave equation.It can accurately simulate the reflection,diffraction,absorption and other effects of electromagnetic waves caused by irregular terrain and complex surface medium.In the previous research,the terrain information is often extracted from the DEM digital map in the prediction of the transmission characteristics of electromagnetic signals in the geographical environment.The electromagnetic model is rough and lack of comprehensive consideration of the surface cover,and the prediction accuracy needs to be further improved.Therefore,based on the parabolic equation propagation prediction model,this paper studies how to build an electromagnetic model which is closer to the real geographical environment.By extracting geographic information from Google earth and airborne LiDAR point clouds,an electric wave propagation model which can simultaneously consider irregular terrain and various surface covers is established,and the influence of geographical environment factors on the propagation characteristics of the wave is simulated and analyzed.Firstly,the LiDAR point cloud data in LAS format are studied,and the extraction of 3D Geographic elevation data is realized by programming.On this basis,the mathematical morphology algorithm is used to deal with the LiDAR point cloud data after the grid.The information of terrain and terrain is obtained.It is prepared for the electromagnetic modeling of the next step of the geographical environment.Secondly,the prediction method of electric wave propagation based on Google earth is studied.The latitude and longitude elevation and satellite image data are extracted from the Google earth.According to the different color features of different objects,the k-means algorithm is used to segment the image,and the category information of the surface cover is obtained,and its setting is matched.The electromagnetic parameters,combined with the latitude and longitude data,set up the wave propagation model which can simultaneously consider the terrain undulation information and the surface electromagnetic environment information.Finally,the PE model is used to simulate and analyze the characteristics of the radio wave propagation in the geographic environment.Finally,in order to introduce the topographic and ground data obtained from the LiDAR point cloud into the calculation of the parabolic equation,the corresponding electromagnetic parameters are given to various terrain,and the computable electromagnetic model is established.The effects of the diffraction and attenuation of the electric wave caused by the terrain and the ground factors are synthetically analyzed by the parabolic equation.Finally,the point cloud classification program and the PE propagation prediction program are encapsulated,and the radio wave propagation prediction software based on LiDAR point cloud is formed.Compared to the traditional electromagnetic modeling method based on the digital elevation model,this method can take into account the effect of the actual ground objects on the propagation characteristics of the wave,so the prediction results will be more accurate and effective.