| The visualization of wireless channel model is of great significance to deeply study the characteristics of wireless channel and even the whole wireless communication system.Therefore,the key to the visualization of wireless channel model is to visualize a certain characteristic of wireless channel.With the development of science and technology,research methods have made great progress.Visualization technology is no longer limited to two-dimensional plane,and began to expand to three-dimensional space.The visualization of wireless channel model is also developing towards three-dimensional visualization.The three-dimensional visualization of wireless channel model depends on the accurate three-dimensional scene,and the visualization effect is obtained by rendering data on the three-dimensional scene.With the development of modeling technology,Oblique photography modeling has become the main means of modeling.The traditional statistical wireless channel modeling method relies on a large amount of data calculation,and the accuracy is not high.The wireless channel modeling method based on ray tracing method can solve the accurate signal trajectory,which has the characteristics of high accuracy.Based on the above theory,this essay designs a scheme to establish a wireless channel model and carry out three-dimensional visualization.The wireless channel model is established by ray tracing method and the field strength is predicted.The three-dimensional scene model is established through the three-dimensional modeling technology of oblique photography.The model is loaded on the web based on the cesium framework.Finally,the prediction results are rendered on the three-dimensional model.This essay studies the related theories of wireless channel modeling,and analyzes the research status and modeling methods of wireless channel modeling.In this essay,ray tracing method is selected as the modeling method,which has higher accuracy than statistical modeling and semi deterministic modeling.The ten ray model is improved and the diffraction process is considered on the basis of this model.Direct,reflection and diffraction paths are obtained by establishing mathematical models.After that,the field strength coverage prediction is carried out to obtain the field strength data of direct field,reflection field and diffraction field.The actual test experiment is designed to verify the results,carrying out the actual test,and obtains the actual data.In this essay,the mean square deviation method is used to compare the data calculated by the empirical model and the data calculated by the ray tracing method with the measured data to verify the high accuracy of the field strength prediction by the ray tracing method.In this essay,the research on 3D modeling of oblique photography is carried out,and the research status and basic principles of oblique photography are described.The modeling steps of oblique photography 3D modeling are described in detail.First,determine the research area according to the requirements,then use the DJI GS Pro software to plan the route,perform the flight task to obtain multi view images,process the image data to ensure the modeling quality,import the processed data into the modeling software for modeling,and then repair the model to make the model more realistic.The built model has a huge amount of data,and the web page will get stuck when loading.So this essay proposes a model segmentation algorithm to segment and simplify the model.When the model is loaded,a model scheduling algorithm is proposed,which uses the scene clipping technology to trim the parts that users can not see outside the screen.For visual presentation,this essay designs a wireless channel model visualization system based on cesium.The system can be used not only for professionals to study the wireless channel model,but also for ordinary users to understand the distribution of electromagnetic wave field strength,so as to solve the problem that the electromagnetic wave can not be observed by the naked eye. |
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