Electromagnetic calculation of complex urban architectual environment based on point cloud reconstruction
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摘要: 在现代城市环境中,地形地貌地物复杂,精确评估电波传播效应十分困难. 针对传统城市建筑环境电磁计算物理建模不够精确的问题,提出利用多视角立体视觉的方法对城市复杂建筑环境进行基于点云的三维重建,获取精确的三角网格模型,并通过机器学习图像分割的方法获取城市环境边界电磁属性;在此基础上进行基于一致性绕射理论的射线追踪电磁计算,从而获取区域范围内的电磁态势分布. 通过在不同分辨率网格模型上计算,并与COST231-Hata模型和实际测量结果对比,高分辨率网格模型的均方根误差为6.065 5 dB,证明了本文建模及计算方法的有效性.Abstract: In a complex city environment, it is very difficult to accurately evaluate the effect of radio wave propagation due to the complex terrain, landforms and features. In order to solve the problem that the traditional physical modeling of electromagnetic computing in urban architectual environment is not accurate enough, this paper proposes a multi-view stereo method to reconstruct the complex urban architectual environment based on point cloud, obtain the accurate triangular mesh model, and obtain the electromagnetic attributes of urban environment boundary by machine learning image segmentation method. On this basis, the ray tracing electromagnetic calculation based on uniform theory of diffraction is carried out to obtain the electromagnetic situation distribution in the region. By calculating on different resolution grid models, and comparing with the COST231-Hata model and actual measurement results, the root mean square error of the high-resolution grid model is 6.0655dB, which proves the effectiveness of the modeling and calculation methods in this paper.
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表 1 仿真参数表
Tab. 1 Simulation parameters table
仿真参数 取值 建筑数量 66 基站高度/m 30 发射功率/W 0.1 载波频率/MHz 355/1 800 虚拟接收机数量 5 551 天线模式 全向天线 带宽/MHz 1 波形 正弦波 极化方式 垂直极化 表 2 实验参数表
Tab. 2 Experimental parameters table
实验参数 取值 实验区域 1.8 km×1.2 km 接收机数量 6 输出功率/W 20 发射天线频率/MHz 355 天线带宽 15 发射机采样点 8 发射机高度/m 2 天线模式 全向天线 天线增益/dBi 3.5 波形 正弦波 极化方式 垂直极化 表 3 三种模型结果对比
Tab. 3 Comparison of 3 model results
模型 面元数 边数 均方根误差/dB 计算时间/s 模型1 17 470 40 246 6.065 5 82 模型2 8 734 20 111 7.922 9 48 模型3 4 384 6 576 8.805 2 21 -
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