Bellhop射线追踪程序概述
1.2 BELLHOP 手册 和 程序日志
BELLHOP- Munk profile frequency = 50.00 Hz
Dummy parameter NMedia = 1
Spline approximation to SSP Attenuation units: dB/mkHz VACUUM
Depth = 5000.00 m
Sound speed profile: z (m) alphaR (m/s) betaR rho (g/cm^3) alphaI betaI
第二步：计算声场并检查输入文件
• 运行BELLHOP的MATLAB命令是：
• bellhop( 'MunkB_ray_2011' )； • 或者 • bellhop 'MunkB_ray_2011'
查看回馈文件 *.prt
BELLHOP/BELLHOP3D
回传输入数据的打印文件MunkB_ray_2011.prt
cLow = 1.0 m/s cHigh = m/s RMax = 1000.000000 km
--------------------------------
Number of source depths = 51
Source depths (m) 0.00 ... 5000.00
Producing source depths by interpolation between sd(1) and sd(2)
C-Linear approximation to SSP Attenuation units: dB/mkHz VACUUM
z (m) alphaR (m/s) betaR rho (g/cm^3) alphaI betaI ( Number of pts = 51 Roughness = 0.00 Depth = 5000.00 ) 0.00 1548.52 0.00 1.00 0.0000 0.0000 200.00 1530.29 0.00 1.00 0.0000 0.0000 250.00 1526.69 0.00 1.00 0.0000 0.0000 400.00 1517.78 0.00 1.00 0.0000 0.0000 600.00 1509.49 0.00 1.00 0.0000 0.0000 800.00 1504.30 0.00 1.00 0.0000 0.0000 1000.00 1501.38 0.00 1.00 0.0000 0.0000 1200.00 1500.14 0.00 1.00 0.0000 0.0000 1400.00 1500.12 0.00 1.00 0.0000 0.0000 1600.00 1501.02 0.00 1.00 0.0000 0.0000 1800.00 1502.57 0.00 1.00 0.0000 0.0000 2000.00 1504.62 0.00 1.00 0.0000 0.0000 2200.00 1507.02 0.00 1.00 0.0000 0.0000 2400.00 1509.69 0.00 1.00 0.0000 0.0000 2600.00 1512.55 0.00 1.00 0.0000 0.0000 2800.00 1515.56 0.00 1.00 0.0000 0.0000 3000.00 1518.67 0.00 1.00 0.0000 0.0000 3200.00 1521.85 0.00 1.00 0.0000 0.0000 3400.00 1525.10 0.00 1.00 0.0000 0.0000 3600.00 1528.38 0.00 1.00 0.0000 0.0000 3800.00 1531.70 0.00 1.00 0.0000 0.0000 4000.00 1535.04 0.00 1.00 0.0000 0.0000 4200.00 1538.39 0.00 1.00 0.0000 0.0000 4400.00 1541.76 0.00 1.00 0.0000 0.0000 4600.00 1545.14 0.00 1.00 0.0000 0.0000 4800.00 1548.52 0.00 1.00 0.0000 0.0000 5000.00 1551.91 0.00 1.00 0.0000 0.0000 Number of pts = 51 ACOUSTO-ELASTIC half-space 5000.00 1600.00 0.00 1.00 0.0000 0.0000
Atoll 射线跟踪操作手册
Aster 射线跟踪模型操作手册 版本：2.5.4目录1介绍 (3)2安装 (4)系统要求和硬件要求 (4)程序安装 (4)硬件狗驱动安装 (6)3地图数据 (6)地图对象数据模拟Above Surface Object Digital Model（ASODM） (6)3.1.1确定性传播类型 (7)3.1.2统计性传播类型 (7)支持的地图数据的不同搭配 (8)3.2.1仅有地物分类地图 (8)3.2.2仅有地物高度地图，无地物分类地图 (8)3.2.3地物高度和地物分类地图都有 (8)3.2.43D Building Vector地图 (8)4Aster模型中的设置 (8)General 标签 (8)Configuration标签 (9)Clutter标签 (10)Geo标签 (11)Ray Tracing标签 (12)5Aster模型预测覆盖图示例 (13)6Aster模型校正 (15)Aster模型 Analysis (15)Aster模型校正 (16)1介绍Aster模型是Atoll中一个可选的射线追踪传播模型，由Forsk公司发布和支持，作为Atoll的一个可选功能。
Aster模型是一个预校正模型，支持所有无线技术，GSM、UMTS、CDMA2000、LTE、Wi-Fi等，支持从150MHz到5GHz范围内的频段。
Aster模型支持所有的小区类型，从微蜂窝小区、迷你蜂窝小区到宏蜂窝小区等等。
支持不同类型的传播环境：密集城区、城区、郊区等，特别适合于带有高精度地图的密集城区环境。
利用CW测量数据，Aster模型可以进行自动模型校正。
Aster模型主要考虑楼顶的垂直衍射和基于射线追踪算法的水平衍射和反射。
本文档主要介绍Aster模型的先进功能特性，及从安装、参数设置到在Atoll中进行使用的过程，主要目的让用户能了解Aster的基本特性，及学会如何在Atoll中使用Aster模型进行计算。
射线追踪法的研究及应用
射线追踪法的研究及应用一、射线追踪法的基本概念大家好，今天咱们聊聊一个看似高深其实也并不那么神秘的话题——射线追踪法。
别被这些专业词吓到，它其实就像是给光线装了一个GPS，让我们可以精确地跟踪每一束光的路径，从而更好地模拟现实世界的视觉效果。
想象一下，你坐在一个屋子里，阳光从窗户照进来，照在桌子上的那一束光线，它是如何在空间中游走的？它和桌面上的物品发生碰撞，又是怎么反射、折射、吸收的？射线追踪法就是通过模拟这些复杂的光线互动，最终生成一张逼真的图像。
你是不是已经开始好奇，射线追踪法到底能做些什么了？别急，咱们慢慢往下看。
最简单的说，射线追踪法就是通过追踪光线从眼睛（相机）出发的路径，一直到它与场景中的物体碰撞、反射、折射后返回眼睛的过程。
每一条光线都要经过很多复杂的计算，这就是为什么它能够创造出极其真实的图像。
说白了，它就是在把世界的每一束光都仔细“读”一遍。
二、射线追踪的应用领域说到射线追踪法的应用，那可真是五花八门，几乎涵盖了我们生活中的方方面面。
最直接的，当然是影视特效和游戏制作。
记得看过那些科幻大片吗？比如《复仇者联盟》里的战斗场面、星际飞船的宇宙漂浮，那些看似轻松、自然的光影变化，背后就离不开射线追踪的帮忙。
想象一下，如果没有射线追踪，电影中的光线就只能是“平面化”的，根本没有那种立体感、深邃感，大家看的时候也许会觉得这画面不够真实，甚至有点假。
再比如，游戏中的画面效果也是如此。
曾经我们玩游戏，画面简直可以用“方块”来形容。
但随着技术的发展，射线追踪被逐步应用到了游戏中，特别是最近几年的一些大作，比如《赛博朋克2077》，就彻底把这个技术带入了玩家的视野。
别的不说，单单是游戏中那个反射效果，让你感受到的真实感就让人目瞪口呆。
你在街头走着，路旁的玻璃店铺、湿漉漉的地面都会反射出你身后的光，仿佛你真的是置身于一个活生生的虚拟世界中。
而这些，都是射线追踪法的“功劳”啊！射线追踪法的作用不仅限于娱乐行业，它在科学领域也是大显身手。
次声波远距离传播射线追踪算法
次声波远距离传播射线追踪算法
摘要：
1.次声波的定义与特点
2.射线追踪算法的概述
3.次声波远距离传播的挑战
4.射线追踪算法在次声波远距离传播中的应用
5.结论
正文：
一、次声波的定义与特点
次声波是指频率低于20Hz 的声波，具有波长较长、传播距离远、能够绕过障碍物等特点。
由于次声波的独特性质，它在很多领域具有广泛的应用前景，如通信、探测、遥感等。
二、射线追踪算法的概述
射线追踪算法是一种在计算机图形学中常用的算法，主要用于追踪光线或射线在三维空间中的传播路径。
这种算法通过计算光线与物体表面的交点，可以确定光线在空间中的传播方向，从而模拟光线的实际传播过程。
三、次声波远距离传播的挑战
次声波在远距离传播过程中会受到多种因素的影响，如大气吸收、散射、折射等。
这些因素会导致次声波的传播路径发生改变，从而降低信号的强度和质量。
为了解决这些问题，需要研究一种有效的传播模型和算法。
四、射线追踪算法在次声波远距离传播中的应用
射线追踪算法可以应用于次声波的远距离传播，通过追踪次声波在空间中的传播路径，可以有效地预测和模拟次声波的传播过程。
此外，射线追踪算法还可以用于优化次声波传播系统的性能，如调整信号的发射方向和强度等。
五、结论
射线追踪算法在次声波远距离传播中具有重要的应用价值，可以有效地解决次声波传播过程中的多种问题。
龙哥库塔法实现短波射线追踪
龙格库塔法实现短波射线追踪马志才摘要：短波是人类最早开发利用的无线电频段，短波通信是历史最为悠久的现代通信手段之一。
短波通信由于设备简单、架设方便、成本低，特别是具有远距离通信的优点，始终在通信领域中占有不可或缺的一席之地。
随着微电子、计算机、数字信号处理等现代电子信息技术的发展，短波通信的性能大为改善，形成了现代短波通信的新技术和新体制。
本文以国际上广泛认可的电离层模型IRI以及地磁场模型为核心进行了数学建模实现，构建了复杂的环境模型。
通过使用Appleton-Hartree公式和Snell定理，利用Runge-Kutta方法并采用数值计算方法完成该复杂环境下的短波射线追踪。
最后利用三维建模，实现射线轨迹的可视化显示。
关键字：电离层、路径参数、射线追踪Short-wave Ray Tracing：Based on Runge-Kutta Method Abstract：Short-wave is the earliest development and utilization radio frequency by human and short-wave communication is one of the oldest modern communication means. As short-wave communication equipment is simple, easy to set up and cost low, especially with the advantage in long-distance communication, it always occupies an essential place in the communication field. With the development of microelectronics, computers, digital signal processing and other modern electronicinformation technology, the short-wave communication performance is improved greatly, and gradually forms new modern short-wave communication technologies and new systems. This paper conducts mathematical modeling to build a complex environmental model. The model uses internationally recognized model of the ionosphere and the geomagnetic field model as the core to achieve. The path parameters of short-wave can be obtained by using the Appleton-Hartree formula and Snell's law. The Runge-Kutta method and the numerical method are used to complete the short-wave ray tracing in complex environment. Finally, this study achieves visual display of ray trajectories by using of three-dimensional modeling.Key words：Ionosphere; path parameters; ray tracing利用电离层“反射”的短波无线电通信是最经济、最常用的远距离无线电通信方式。
射线检测的主要方法及原理ppt正式完整版
当相射比线 于通其过它被的检常测规物无体损时检，测物技体术中，有射缺线陷检的测部技位术（的如主气要孔特、点非是金：属夹杂等）与无缺陷部位对射线的吸收能力不同，一般情况是透过有缺陷部位的射线强度高于无缺陷部位的射线强 度（，4）因研此究可：以弹通道过、检爆测炸透、过核被技检术物、体铸后造的工射艺线等强动度态的过差程异研，究来，判考断古被研检究物，体反中馈是工否程存等在缺陷。
（c）焦（2）电离检测法
当射线通过气体时，与气体分子撞击， 产生电离。电离效应会产生电流，其大小 与射线强度有关，根据电流大小便可判断 试件的完整性。
特点：自动化程度高，成本低，但对 缺陷性质的判别较困难，只适用于形状简 单、表面平整的工件。
电离检测示意图
特点：自动化程度高，但灵敏度较低，对形状复杂的零件 检查也比较困难。
三、射线检测技术的应用
射线检测技术适用于各种材料的检验，应用领域非常广 泛，其常用范围如下： （1）探伤：铸造、焊接工艺缺陷检验，复合材料构建检验等； （2）测厚：厚度在线实时测量； （3）检查：机场、车站、海关检查，结构和尺寸测定等； （4）研究：弹道、爆炸、核技术、铸造工艺等动态过程研究， 考古研究，反馈工程等
谢谢
射线检测技术的主要特点
对被检工件无特殊要求，检测结果显示直观 检测结果可以长期保存 检测技术和检验工作质量可以自我监督 适宜于体积型缺陷
二、射线检测技术的基本原理和方法
三、射线检测技术1的应、用 X射线检测原理
航空、航天关重件检测、科学研究 （13）照荧相光法屏（直接X射观线察检法测常用方法）
气孔、非金属夹杂等）与无缺陷部位对射线的吸收能力 对（被3）检荧工光件屏无直特接殊观要察求法，检测结果显示直观
射线和光线追踪
跨平台应用：支持 多种操作系统和设 备，实现跨平台的 应用和协作
射线与光线追踪技术的前景展望
添加标 题
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技术创新：随着计算 机技术的不断发展， 射线与光线追踪技术 将更加高效和精确， 为虚拟现实、电影制 作等领域带来更多可
能性。
应用领域拓展：除了 传统的电影和游戏制 作，射线与光线追踪 技术还将应用于医疗、 建筑设计等领域，为 专业人员提供更准确 的模拟和预测工具。
硬件设备升级：随着 光线追踪技术的普及， 未来将会有更多支持 光线追踪的显卡和其 他硬件设备问世，提 升用户的视觉体验。
跨领域合作：射线与 光线追踪技术将促进 不同领域之间的合作， 如电影制作、建筑设 计、游戏开发等，推 动各行业的技术进步
和融合发展。
射线与光线追踪技术面临的挑战和机遇
挑战：计算量大，实时渲染难度高
光线追踪技术可以模拟真实的光线行为，因此可以生成逼真的图像效果，广泛应用于电影制作、 游戏开发和建筑设计等领域。
光线追踪技术的优缺点
优点：真实感 强，能够模拟 光线在现实世 界中的传播方 式，实现更加 逼真的渲染效
果。
缺点：计算量 大，需要大量 的计算资源和 时间，对硬件 设备要求较高。
适用场景：适 用于电影、游 戏等需要高精 度渲染的领域。
优点：精确度高，能够模拟光线在 真实世界中的传播路径，适用于复 杂的光线交互场景。
应用场景：适用于电影制作、游戏 开发、建筑设计等领域，可以模拟 光线在物体表面反射、折射、漫反 射等效果。
添加标题
缺点：计算量大，需要大量的内存 和计算资源，需要高性能计算机才 能实现实时渲染。
游戏开发：实时渲染高质量图像，提高游戏体验 电影制作：模拟真实光影效果，增强视觉效果 建筑设计：可视化建筑模型，便于评估和修改设计方案 虚拟现实：提供沉浸式体验，提高虚拟世界的真实感
BELLHOP使用指南v2.2
BELLHOP 使用指南 V2.2
修改记录
1. 修改 V2.1 版本中第六章波形文件的波形文件的验证图。 2. 修改 V2.1 版本中第三章的“其他参数”。 3. 增加第六章中 BELLHOP 与射线模型的对比。 4. 增加第七章中 BELLHOP 的时变特性的改进。
-1-
BELLHOP 使用指南 V2.2
五、OPTIONS4 ................................................................................................................ - 12 1. 2. OPTIONS4(1)......................................................................................................... - 12 OPTIONS4(2)......................................................................................................... - 12 -
六、其他参数 ................................................................................................................. - 13 第四章 BELLHOP（Matlab_GUI）实例一 ......................................................................... - 15 一、准备工作 ................................................................................................................. - 15 -
Atoll 射线跟踪操作手册
Aster 射线跟踪模型操作手册 版本：2.5.4目录1介绍 (3)2安装 (4)系统要求和硬件要求 (4)程序安装 (4)硬件狗驱动安装 (6)3地图数据 (6)地图对象数据模拟Above Surface Object Digital Model（ASODM） (6)3.1.1确定性传播类型 (7)3.1.2统计性传播类型 (7)支持的地图数据的不同搭配 (8)3.2.1仅有地物分类地图 (8)3.2.2仅有地物高度地图，无地物分类地图 (8)3.2.3地物高度和地物分类地图都有 (8)3.2.43D Building Vector地图 (8)4Aster模型中的设置 (8)General 标签 (8)Configuration标签 (9)Clutter标签 (10)Geo标签 (11)Ray Tracing标签 (12)5Aster模型预测覆盖图示例 (13)6Aster模型校正 (15)Aster模型 Analysis (15)Aster模型校正 (16)1介绍Aster模型是Atoll中一个可选的射线追踪传播模型，由Forsk公司发布和支持，作为Atoll的一个可选功能。
Aster模型是一个预校正模型，支持所有无线技术，GSM、UMTS、CDMA2000、LTE、Wi-Fi等，支持从150MHz到5GHz范围内的频段。
Aster模型支持所有的小区类型，从微蜂窝小区、迷你蜂窝小区到宏蜂窝小区等等。
支持不同类型的传播环境：密集城区、城区、郊区等，特别适合于带有高精度地图的密集城区环境。
利用CW测量数据，Aster模型可以进行自动模型校正。
Aster模型主要考虑楼顶的垂直衍射和基于射线追踪算法的水平衍射和反射。
本文档主要介绍Aster模型的先进功能特性，及从安装、参数设置到在Atoll中进行使用的过程，主要目的让用户能了解Aster的基本特性，及学会如何在Atoll中使用Aster模型进行计算。
BELLHOP模型
The BELLHOP Manual and User’s Guide: PRELIMINARY DRAFTMichael B.PorterHeat,Light,and Sound Research,Inc.La Jolla,CA,USAJanuary31,2011AbstractBELLHOP is a beam tracing model for predicting acoustic pres-surefields in ocean environments.The beam tracing structure leads to a particularly simple algorithm.Several types of beams are imple-mented including Gaussian and hat-shaped beams,with both geomet-ric and physics-based spreading laws.BELLHOP can produce a vari-ety of useful outputs including transmission loss,eigenrays,arrivals, and received time-series.It allows for range-dependence in the top and bottom boundaries(altimetry and bathymetry),as well as in the sound speed profile.Additional inputfiles allow the specification of directional sources as well as geoacoustic properties for the bounding media.Top and bottom reflection coefficients may also be provided. BELLHOP is implemented in Fortran,Matlab,and Python and used on multiple platforms(Mac,Windows,and Linux).This report describes the code and illustrates its use.12Contents1Map of the BELLHOP program51.1Input (5)1.2Output (5)2Sound speed profile and ray trace9 3Eigenray plots17 4Transmission Loss214.1Coherent,Semicoherent,and Incoherent TL (25)5Directional Sources27 6Range-dependent Boundaries316.1Piecewise-Linear Boundaries:Dickins seamount (31)6.2Plotting a single beam (34)6.3Curvilinear Boundaries:Parabolic Bottom (35)7Tabulated Reflection Coefficients39 8Range-dependent Sound Speed Profiles41 9Arrivals calculations and broadband results459.1Coherent and Incoherent TL (45)9.2Plotting the impulse response (51)9.3Generating a receiver timeseries (53)10Acknowledgments57341Map of the BELLHOP program1.1InputThe overall structure of BELLHOP is shown in Fig.(1).Variousfiles must be provided to describe the environment and the geometry of sources and receivers.In the simplest case,which is also typical,there is only one such file.It is referred to as an environmentalfile and includes the sound speed profile,as well as information about the ocean bottom.However,if there is a range-dependent bottom,then one must add a bathymetryfile with range-depth pairs defining the water depth.Similarly,if there is a range-dependent ocean sound speed,the one must an an SSPfile with the sound speed tabulated on a regular grid.Further,if one wants to specify an ar-bitrary bottom reflection coefficient to characterize the bottom,then one must provide a bottom reflection coefficientfile with angle-reflection coeffi-cient pairs defining the reflectivity.Similar capabilities are implemented for the surface.Thus there is the option of providing a top reflection coefficient and a top shape(called an altimetryfile).Usually one assumes the acoustic source is omni-directional;however,if there is a source beampattern,then one must provide a source beam pattern file with angle-amplitude pairs defining it.BELLHOP reads thesefiles depending on options selected within the main environmentalfile.Plot programs(plotssp,plotbty,plotbrc,etc.)are provided to display each of the inputfiles.1.2OutputBELLHOP produces different outputfiles depending on the options selected within the main environmentalfile.Usually one starts with a ray tracing option,which produces afile con-taining a fan of rays emanating from the source.If the eigenray option is selected,then the fan is winnowed to include only the rays that bracket a specified receiver location.Thefile format is identical to that used in the standard ray-tracing option.Rayfiles are usually used to get a sense of how energy is propagating in the channel.The program plotray is used to display thesefiles.Usually one is interested in calculating the transmission loss for a tonal source(or for a single tone of interest in a broadband waveform).The transmission loss is essentially the sound intensity due to a source of unit strength.The transmission loss information is written to a shadefile which5plotrayplotshdplottlrplotarrsource timeseries generatorplotts plotsspplotbtyplotbrcplotssp2DFigure1:BELLHOP structure.6can be displayed as a2D surface using plotshd,or in range and depth slices, using plottlr and plottld respectively.If one wants to get not just the intensity due to a tonal source,but the entire timeseries then one selects an arrivals calculation.The resulting arrivalsfile contains amplitude-delay pairs defining the loudness and delay for every echo in the channel.This information can be plotted using plotarr to show the echo pattern.Alternatively it can be passed to a convolver, which sums up the echoes of a particular source timeseries to produce a receiver timeseries.The program plotts can be used to plot either the source or receiver timeseries.782Sound speed profile and ray traceAs afirst example,we consider a deep water case with the Munk sound speed profiually one should start by plotting the sound speed profile and doing a ray trace.The inputfile(also called an environmentalfile)isa simple textfile created using any standard text editor and must have a’.env’extension.It is usually easiest to start from one of the examplefiles.Here we consider at/tests/Munk/MunkB ray.env:MunkB ray.env1’Munk profile’!TITLE250.0!FREQ(Hz)31!NMEDIA4’SVF’!SSPOPT(Analytic or C-linear interpolation) 5510.05000.0!DEPTH of bottom(m)60.01548.52/7200.01530.29/8250.01526.69/9400.01517.78/10600.01509.49/11800.01504.30/121000.01501.38/131200.01500.14/141400.01500.12/151600.01501.02/161800.01502.57/172000.01504.62/182200.01507.02/192400.01509.69/202600.01512.55/212800.01515.56/223000.01518.67/233200.01521.85/243400.01525.10/253600.01528.38/263800.01531.70/274000.01535.04/284200.01538.39/294400.01541.76/304600.01545.14/314800.01548.52/325000.01551.91/33’A’0.0345000.01600.000.01.0/351!NSD361000.0/!SD(1:NSD)(m)3751!NRD380.05000.0/!RD(1:NRD)(m)9391001!NR400.0100.0/!R(1:NR)(km)41’R’!’R/C/I/S’4241!NBeams43-20.020.0/!ALPHA1,2(degrees)440.05500.0101.0!STEP(m),ZBOX(m),RBOX(km) The inputfile is read using list-directed i/o,so the data does not need to be precisely positioned on each line.As a convenience we also append comments,preceded by’!’.These are optional and are not read by the program.The source frequency(line2)is not terribly important for the basic ray trace.The rays are frequency independent;however,the frequency can have an impact on the ray step size,since the code assumes more accurate ray trajectories will be needed at higher frequencies.NMedia(line3)is always set to one in BELLHOP.This parameter is included for compatibility with other models in the Acoustics Toolbox,which are capable of handling multi-layered problems.The top option(line4)is next specifed as‘SVF’indicating that a spline fit should be used to interpolate the sound speed profile;that the ocean sur-face is modeled as a vacuum;and that all attenuation values are specified in dB/mkHz.We chose the splinefit here knowing that the profile is smoothly varying.In such cases,the splinefit produces smoother looking ray trace plots.The only important parameter in the next line(5)is the bottom depth (5000m),which indicates the last line that needs to be read in the sound speed profile.Thefirst two parameters are not used by BELLHOP.Next we see a sequence of depth-soundspeed pairs defining the ocean soundspeed profile.The last value in the soundspeed profile must start with the previously specified value for the bottom depth.To ensure compatibility with the other models in the Acoustics Toolbox,we normally terminate each line with a’/’.The other models are expecting attenuations,shear speeds, and a density as additional parameters and the’/’tells them to stop reading the line and use default values.Next we have two lines specifying the bottom boundary.The option letter‘A’indicates that the bottom is to be modeled as an Acousto-Elastic halfspace.The lines following specify that halfspace as having a sound speed of1500m/s and unit density(which is not very realistic).The next6lines specify the source depths,receiver depths,and receiver ranges.Depths are always specified in meters and ranges in kilometers.10For ourfirst run,we are producing a ray trace so the receiver locations are irrelevant;however,they do need to be provided.Note also that51 receiver depths have been specified.Often the user simply wants a uniform distribution of receiver depths to display the acousticfield.To avoid forcing the user to type in all those numbers one has the option of simply putting in thefirst and last values and terminating the line with a’/’.The code detects the premature termination and then produces a full set of receivers by interpolation.The sources and receivers must lie within the interior of the waveguide.The choice of units is motivated by typical ocean acoustic scenarios. However,fundamentally the code is simply solving the wave equation so any self-consistent set of units could be used.Next is the RunType(line41).For a raytrace run,we select option‘R’. The following lines then specify the fan that will be used,given as a number of rays,together with the angular limits in degrees.We follow a convention that the angles are specified in declination,i.e.zero degrees is a horizontally launched ray,and a positive angle is a ray launched towards the bottom.For a ray trace run,the plot usually becomes too cluttered if we use more than about50rays.This is a matter of taste.Likewise,the angular limits are determined by what part of thefield the user is interested in seeing.The last line(44)specifies the step size in meters used to trace a ray, along with the depth and range of a box beyond which no rays are traced. Usually,a step size of0should be selected and then BELLHOP will make an automatic selection of about a tenth of the water depth.Regardless of what step size is selected,BELLHOP dynamically adjusts the step size as the ray is traced,to ensure that each ray lands precisely on all depths where a sound speed is given.Thus,the sound speed profile itself usually controls the ray step size.If you provide more sound speed points than are necessary, BELLHOP will similarly run slower.On the other hand,for a given sampling of the sound speed profile,you may be able to obtain a more accurate ray trace by specifying a step size that is smaller than the default value.Now that the inputfile has been created,we can start by plotting the soundspeed profile,using the Matlab routine plotssp.m.The syntax of the Matlab command to run this is:plotssp’MunkB ray’where’MunkB ray.env’is the name of the BELLHOP inputfile.This pro-duces the plot in Fig.(2).1115001510152015301540155015600500100015002000250030003500400045005000Sound Speed (m/s)D e p t h (m )Figure 2:The Munk sound speed profile.We started first with the sound speed profile plot,to introduce the sce-nario in a logical fashion.However,in practice it is recommended to do a trial BELLHOP run on the input file first.BELLHOP will produce a print file as show below,which echoes the input data in a clear format.In addition,it will stop at the first place it encounters something unintelligible.Thus,by examining the print file one can usually see clearly any formatting errors.MunkB ray.prt1BELLHOP-Munkprofile 2frequency =50.00Hz34Dummy parameter NMedia =156SPLINE approximation to SSP7Attenuation units:dB/mkHz 8VACUUM 910Depth =5000.0000000000000m1112Spline SSP option 1314Sound speed profile:150.001548.5216200.001530.2917250.001526.6918400.001517.781219600.001509.4920800.001504.30211000.001501.38221200.001500.14231400.001500.12241600.001501.02251800.001502.57262000.001504.62272200.001507.02282400.001509.69292600.001512.55302800.001515.56313000.001518.67323200.001521.85333400.001525.10343600.001528.38353800.001531.70364000.001535.04374200.001538.39384400.001541.76394600.001545.14404800.001548.52415000.001551.914243(RMS roughness=0.00)44ACOUSTO-ELASTIC half-space455000.001600.000.00 1.000.00000.0000 4647Number of sources=148Source depths(m)491000.005051Number of receivers=5152Receiver depths(m)530.00000100.000200.000300.000400.000 54500.000600.000700.000800.000900.000 551000.001100.001200.001300.001400.00 561500.001600.001700.001800.001900.00 572000.002100.002200.002300.002400.00 582500.002600.002700.002800.002900.00 593000.003100.003200.003300.003400.00 603500.003600.003700.003800.003900.00 614000.004100.004200.004300.004400.00 624500.004600.004700.004800.004900.00 635000.006465Number of ranges=100166Receiver ranges(km)670.000000.1000000.2000000.3000000.40000013680.5000000.6000000.7000000.8000000.90000069 1.00000 1.10000 1.20000 1.30000 1.4000070 1.50000 1.60000 1.70000 1.80000 1.9000071 2.00000 2.10000 2.20000 2.30000 2.4000072 2.50000 2.60000 2.70000 2.80000 2.9000073 3.00000 3.10000 3.20000 3.30000 3.4000074 3.50000 3.60000 3.70000 3.80000 3.9000075 4.00000 4.10000 4.20000 4.30000 4.4000076 4.50000 4.60000 4.70000 4.80000 4.9000077 5.0000078...100.0000007980Ray trace run81Geometric beams82Point source(cylindrical coordinates)83Rectilinear receiver grid:Receivers at rr(:)x rd(:)8485Number of beams=4186Beam take-off angles(degrees)87-20.0000-19.0000-18.0000-17.0000-16.000088-15.0000-14.0000-13.0000-12.0000-11.000089-10.0000-9.00000-8.00000-7.00000-6.0000090-5.00000-4.00000-3.00000-2.00000-1.00000910.00000 1.00000 2.00000 3.00000 4.0000092 5.00000 6.000007.000008.000009.000009310.000011.000012.000013.000014.00009415.000016.000017.000018.000019.00009520.00009697Step length,deltas=500.00000000000000m9899Maximum ray Depth,zBox=5500.0000000000000m100Maximum ray range,rBox=101000.00000000000m101No beam shift in effect102103104105CPU Time=0.781E-01sThe Matlab command to run BELLHOP is:bellhop’MunkB ray’where’MunkB ray.env’is the name of the inputfile.Assuming a successful completion,BELLHOP produces a print-file called’MunkB ray.prt’and a rayfile called’MunkB ray.ray’.One should carefully examine the printfile to verify that the problem was set up as intended and that BELLHOP ran to14012345678910x 1040500100015002000250030003500400045005000Range (m)D e p t h (m )BELLHOP− Munk profileFigure 3:Ray trace for the Munk sound speed profile.completion.The latter can be verified by checking that there are no error messages in the print file,and that the last line of the print file shows the CPU time used.The next step is to plot the rays using the Matlab command:plotray ’MunkB ray’This produces the plot in Fig.(3).Notice that the range axis is in me-ters.If kilometers are preferred,then one simply sets the global Matlab variable:units =’km’The rays have are plotted using different colors depending on whether the ray hits one or both boundaries.The number of surface and bottom bounces are written to the ray file so it is simple to modify plotray to color code the rays in whatever way best illustrates the propagation physics.15163Eigenray plotsBELLHOP can also produce eigenray plots showing just the rays that con-nect the source to a receiver.To do this,one simply changes the RunType to‘E’.However,to run this reliably one should understand the way this is implemented.The code does exactly the same computation as is done for a regular ray trace;however,it only saves the rays to the rayfile,whose as-sociated beams makes a contribution to the specified receiver points.There are many implications in this statement.First,one should be aware of which beam type is used.For a true eigenray calculation one should use the default beam,which has a beamwidth defined by the ray tube formed by adjacent rays.We call that a geometric beam.The default beam also has a hat-shape in the traditionalfinite element style,so that it vanishes outside the neighboring rays of the central ray of the beam.Other beam types,such as the Cerveny,Popov,Psencik beams are generally much broader beams,and so one would get lots of additional rays that pass at greater distances from the receiver.When we use the default beam type,the rays that are written will be only the bracketing rays for the receiver location.Second,one typically needs to use a muchfiner fan.For instance,if one used41rays as we did in the previous example,then the rays are quite spread out at long ranges.Then when we save the bracketing rays,they may still miss the receiver location by a wide margin.For this example,we therefore increase the number of rays to5001.The more rays used,the more precise the eigenray calculation will be.However,the run time will increase accordingly.Finally,one should generally do an eigenray calculation with just a single source and receiver.Otherwise,the resulting ray plot would be too cluttered.The inputfile MunkB eigenray.env with these changes is shown below.The eigenrays are plotted using the usual plotray command,yielding the plot in Fig.(4).MunkB eigenray.env1’Munk profile’!TITLE250.0!FREQ(Hz)31!NMEDIA4’CVF’!SSPOPT(Analytic or C-linear interpolation) 5510.05000.0!DEPTH of bottom(m)60.01548.52/7200.01530.29/8250.01526.69/9400.01517.78/10600.01509.49/11800.01504.30/17121000.01501.38/131200.01500.14/141400.01500.12/151600.01501.02/161800.01502.57/172000.01504.62/182200.01507.02/192400.01509.69/202600.01512.55/212800.01515.56/223000.01518.67/233200.01521.85/243400.01525.10/253600.01528.38/263800.01531.70/274000.01535.04/284200.01538.39/294400.01541.76/304600.01545.14/314800.01548.52/325000.01551.91/33’A’0.0345000.01600.000.01.0/351!NSD361000.0/!SD(1:NSD)(m)371!NRD38800.0/!RD(1:NRD)(m)391!NR40100.0/!R(1:NR)(km)41’E’!’R/C/I/S’425001!NBeams43-25.025.0/!ALPHA1,2(degrees)440.05500.0101.0!STEP(m),ZBOX(m),RBOX(km)18012345678910x 1040500100015002000250030003500400045005000Range (m)D e p t h (m )BELLHOP− Munk profileFigure 4:Eigenrays for the Munk sound speed profile with the source at 1000m and the receiver at 800m.19204Transmission LossWe can calculate transmission loss by selecting RunType=‘C’as shown in the listing below.As we will discuss in more detail shortly,‘C’stands for Coherent pressure calculations.The pressurefield,p,is then calculated for the specified grid of receivers,with a scaling such that20log10(|p|)is the transmission loss in dB.One may also select multiple source depths,in which case BELLHOP does a run in sequence for each source depth.The frequency(here50Hz)is now a very important parameter,since the inter-ference pattern is directly related to the wavelength.The frequency also affects the attenuation,when present.The number of beams,NBeams,should normally be set to0,allow-ing BELLHOP to automatically select the appropriate value.The number needed increases with frequency and the maximum range to a receiver.To understand this one may imagine a point source in free space.The beam fan expands as we go away from the source.Meanwhile,thefield at a given point is essentially an interpolation between adjacent beams.To accurately interpolate we need the wavefronts of adjacent beams to be sufficiently close.MunkB coh.env1’Munk profile,coherent’!TITLE250.0!FREQ(Hz)31!NMEDIA4’CVW’!SSPOPT(Analytic or C-linear interpolation) 5510.05000.0!DEPTH of bottom(m)60.01548.52/7200.01530.29/8250.01526.69/9400.01517.78/10600.01509.49/11800.01504.30/121000.01501.38/131200.01500.14/141400.01500.12/151600.01501.02/161800.01502.57/172000.01504.62/182200.01507.02/192400.01509.69/202600.01512.55/212800.01515.56/223000.01518.67/233200.01521.85/243400.01525.10/253600.01528.38/263800.01531.70/21274000.01535.04/284200.01538.39/294400.01541.76/304600.01545.14/314800.01548.52/325000.01551.91/33’A’0.0345000.01600.000.01.80.8/351!NSD361000.0/!SD(1:NSD)(m)37201!NRD380.05000.0/!RD(1:NRD)(m)39501!NR400.0100.0/!R(1:NR)(km)41’C’!’R/C/I/S’420!NBEAMS43-20.320.3/!ALPHA1,2(degrees)440.05500.0101.0!STEP(m),ZBOX(m),RBOX(km)BELLHOP tends to be conservative in selecting the number of beams, assuming that the details of the interference pattern in the acousticfield are important.That makes sense for benchmarking applications,or often for lower frequencies.However,as we go to higher frequencies,e.g.10kHz, the environmental uncertainty in a real world case,makes it impossible to replicate these patterns(as they would be observed in a sea test)in detail.You may then wish to experiment with reducing the number of beams to save run time.The next step is to plot thefield using the Matlab command: plotshd’MunkB Coh’However,we can also do a multipanel plot using:plotshd(’MunkB Coh’,2,2,1)where’2,2,1’tells Matlab that we wish to use thefirst panel in a2x2 set.We repeat for several other cases discussed shortly,to produce the plot in Fig.(5).The lower two TL plots are reference solutions calculated by KRAKEN and SCOOTER respectively,which are other models in the Acous-tics Toolbox.They may be considered exact.Most people would consider the agreement between BELLHOP and the other models to be excellent.People are also usually surprised to see that this occurs at50Hz,which is considered a low frequency in a certain taxonomy.Ray/beam methods are22based on high-frequency asymptotics so the incorrect prejudice is that they are not suitable for this sort of problem.We observe thatfine details of the interference pattern are reproduced correctly.That interference pattern results from the ensemble of propagating beams and they must all add up in the right place and with the right phase.Thus,this case provides a rigorous test of the numerics.Nevertheless,we can identify some well-known artifacts of classical ray theory,namely the perfect shadows and the caustics.These are places where thefield goes to zero of infinity,respectively.For better accuracy,we invoke the Gaussian beam option.The specific type of beam used is selected using the second letter in RunType.If,as in the above,we omit the second letter,the code uses option‘G’for geometric beams.Selecting RunType=‘CB’(B for beam), yields the result in the upper right panel.This produces some leakage energy in the shadow zones and smooths out the caustics.In general,wefind this option produces more accurate TL plots.However,the geometric beam option is left as the default since people are usually most familiar with that approach.23Range (km)D e p t h (m )BELLHOP− Munk profile, coherent Freq = 50 Hz Sd = 1000 m501000100020003000400050005060708090100Range (km)D e p t h (m )BELLHOP− Munk profile (Gaussian beam option)100020003000400050005060708090100Range (km)D e p t h (m )KRAKEN− Munk profile0100020003000400050005060708090100Range (km)D e p t h (m )SCOOTER−Munk profile0100020003000400050005060708090100Figure 5:Transmission loss for the Munk sound speed profile using a)geo-metric beams,b)Gaussian beams,c)KRAKEN normal modes,d)SCOOTER wavenumber integration.244.1Coherent,Semicoherent,and Incoherent TLAs discussed above,RunType=‘C’produces a so-called coherent TL calcu-lation.By simply changing thatfirst option letter to‘S’,or‘I’we produce semi-coherent and incoherent TL calculations,respectively.For each of these options one may use the second letter to select the type of beam(geometric or Gaussian).The full set of combinations is shown in Fig.(6).The motivation for the incoherent TL option is that sometimes the de-tails of the interference pattern are not meaningful.For instance,if we consider an acoustic modem operating in the10-15kHz band,then the in-terference pattern will vary widely across the band.It will also be very sensitive to details of the sound speed profile that are not measurable.The individual TL plots are representative samples of what might be seen at a given frequency,but cannot be considered as deterministic forecasts.With that in mind,one may be just as happy to get a TL averaged(loosely speak-ing)across all the frequencies.There are many ways to get such averaged TL surfaces.In ray models, we typically throw away the phase of each path,while in mode models we throw away the phase of the individual modes.The effects are not the same.However,these are both reasonable approaches to capturing a smoothed energy level.Hence,the very smoothedfigures seen at the bottom of Fig.(6).The user must decide for herself which display captures the relevant information for her particular application.The middle panel shows a semi-coherent calculation which preserves some,but not all of the interference effects.The motivation for this op-tion is that one may have a mid-frequency source near the surface.The frequency is sufficiently high that many of the interference effects are not significant or reliably predictable.However,a core feature is the interfer-ence with the surface image,i.e.the reflection of the source in the mirror formed by the ocean surface.Because the source is close to the surface this basic radiation pattern is a stable feature even at higher frequencies.The semi-coherent option captures this effect by putting a Lloyd mirror pattern in for the source beam pattern,but throwing away the phase of the rays.In practice,we have rarely used this option.The incoherent and semi-coherent TL options attempt to capture less of the detail of the acousticfield.As a result,BELLHOP can be run with less stringent accuracy requirements(fewer beams and larger step sizes).This in turn can save on the run time.25Range (km)D e p t h (m )BELLHOP− Munk profile, coherent Freq = 50 Hz Sd = 1000 m050100200040006080100Range (km)D e p t h (m )BELLHOP− Munk profile, coherent, Gaussian beamFreq = 50 Hz Sd = 1000 m200040006080100Range (km)D e p t h (m )BELLHOP− Munk profile, semi−coherentFreq = 50 Hz Sd = 1000 m200040006080100Range (km)D e p t h (m )BELLHOP− Munk profile, semi−coherent, Gaussian beamFreq = 50 Hz Sd = 1000 m200040006080100Range (km)D e p t h (m )BELLHOP− Munk profile, incoherentFreq = 50 Hz Sd = 1000 m200040006080100Range (km)D e p t h (m )BELLHOP− Munk profile, incoherent, Gaussian beamFreq = 50 Hz Sd = 1000 m200040006080100Figure 6:Transmission loss for the Munk sound speed profile using (top to bottom)coherent,semi-coherent,and incoherent TL calculations;and left to right geometric and Gaussian beams.265Directional SourcesWe considerfirst a point source in free space(in a homogeneous medium).The BELLHOP environmentalfile uses a sound speed profile going from ±10000m in depth.The depth interval is selected there to cover the range over which we are interested in seeing thefield,since BELLHOP will only calculate thefield within the waveguide.To make sure there are no boundary reflections,we use the Acousto-Elastic halfspace option with a sound speed and density precisely matching that within the water column.We set NBeams and Step to zero,letting the code automatically select appropriate values.The environmentalfile for this case is shown below and the resulting TL plot is shown in the upper panel of Fig.(7).omni.env1’Point source in free space’2100.0!Frequency(Hz)314’CAF’5-10000.01500.00.01.0/615000.010000.07-10000.01500.00.01.0/810000.0/9’A’0.010/111!NSD120.0/!SD(1:NSD)13501!NRD14-5000.05000.0/!RD(1:NRD)15501!NR16-10.010.0/!R(1:NR)(km)17’C’!Run type:’Ray/Coh/Inc/Sem’180!NBEAMS19-180180/!ALPHA1,2(degrees)200.010001.010.0!STEP(m),ZBOX(m),RBOX(km)21Directional sources are commonly used in underwater acoustics.Often, the directional patterns are generated by adjusting the phase and amplitude of a discrete set of omni-directional projectors.One may model such sources using BELLHOP or any of the other models in the Acoustics Toolbox,by simply running the model for each source position and then summing up the resulting acousticfields using that same phase and amplitude weighting.This is often the most faithful approach;however,it has the disadvantage of27。
射线跟踪课件.ppt
的边缘、拐角、尖
顶和凸曲面时，会
产生一新的绕射射
线。图2.2所示的是 边缘绕射情况。
图2.2边缘绕射
凯勒指出，边缘绕射射线与边缘的夹角等于入射射线与
边缘的夹角。一条入射射线会激起无穷多条绕射射线，它们都
位于一个以绕射点为顶点的圆锥面圆锥的半顶角等于入射射线与边缘切线的夹角。
二、直射波、反射波、绕射波
2.1 反射定律和折射定律
射线在传播中遇到不同媒质的分界面时，将发生反射和折射
现象，由费马原理可以推导出反射射线和折射射线遵循的传播
规律，即反射定律和折射定律。
反射定律包括三个内容:
(1)反射射线、反射点处反射面法线及入射射线在同一平面内；
（2）反射射线、入射射线分居法线两侧；
即可得到接受点直射波的电场强度大小。
2.4.2 反射波和折射波的电场强度计算
根据电磁场理论，可求得平行极化波的反射系数R 和折射 系数 T 及垂直极化波的反射系数 R 和折射系数 T 。
对于任何线极化入射波，都可以根据入射平面，分解为平
2.3 实际源、虚拟源的有效区域
在整个传播环境中，通常有三类射线：一类是由发射源所
产生的直射线，一类是由墙面的镜像反射所产生的反射线，由 镜像理论可知，这些反射线可以看作是一个虚拟源——实际源 的镜像所产生的；另一类是由墙角发生绕射时所产生的绕射线， 同样这些绕射线也可以看作是一个虚拟源——绕射源所产生的。 因此整个传播环境中的射线就相当是由三类源所产生的，它们 分别是发射源、镜像源(或者反射源)以及绕射源，这三类源的 位置分别由发射机天线的位置、镜像的位置以及绕射点的位置 (即发生绕射的墙角的位置)所确定。
图2.3.a辐射源可视区域 图 2.3.b反射面可视区域 图2.3三种可视区域
bellhop使用手册
bellhop使用手册摘要：1.引言2.bellhop 的安装和使用3.bellhop 的主要功能4.如何使用bellhop 进行对话5.bellhop 的训练和优化6.bellhop 的局限性和未来发展7.总结正文：1.引言bellhop 是一款先进的对话机器人，可以帮助用户快速获得信息、解决问题、完成任务等。
本文将介绍bellhop 的使用手册，帮助用户更好地了解和使用这一工具。
2.bellhop 的安装和使用首先，用户需要下载并安装bellhop。
安装完成后，用户可以通过各种途径与bellhop 进行交互，例如通过语音、文字、图像等方式。
3.bellhop 的主要功能bellhop 的主要功能包括问答、任务执行、推荐服务、数据分析等。
用户可以通过与bellhop 对话，获得关于天气、新闻、音乐等信息，或者让bellhop 帮忙完成一些简单的任务，例如预约餐厅、购买电影票等。
4.如何使用bellhop 进行对话与bellhop 进行对话非常简单。
用户只需要说出自己的需求或者问题，bellhop 会尽力理解并给出相应的回答。
如果bellhop 无法理解用户的意思，它会提示用户重新表达问题或者提供更多信息。
5.bellhop 的训练和优化为了提高bellhop 的性能和准确度，用户可以通过与bellhop 交互来训练和优化它。
用户可以对bellhop 的回答进行评价和反馈，帮助它更好地理解用户的需求和意图。
6.bellhop 的局限性和未来发展虽然bellhop 在对话理解和任务执行方面已经取得了很大的进展，但它仍然存在一些局限性，例如对于一些复杂的问题或者任务，它的回答可能不够准确或者完整。
在未来，我们将继续努力优化和扩展bellhop 的功能，为用户提供更加智能化和便捷的服务。
7.总结bellhop 是一款非常实用的对话机器人，可以帮助用户快速获得信息、解决问题、完成任务等。
射线追踪
(Accepted for publication 2 April 1996) Seismic refraction analysis is presented for uniformly deposited shallow soil strata with wave velocity increasing continuously with depth due to differential compaction effects. Closed form solutions of the surface-to-surface travel time as well as for the depth to maximum penetration are derived for realistic velocitydepth functions. An inversion procedure based on simple formulas is presented and its applicability is demonstrated and discussed. The method takes into account the information along the entire refraction line in one step, in contrast to the discrete ray-tracing technique and is, therefore, less sensitive to the natural scatter of the data. Copyright © 1996 Elsevier Science Limited
382
C. Vrettos
The parametric equation for the depth z=
射线跟踪算法应用综述
射线跟踪算法应用综述黎讴1，李晖晖2(1 中科院广州电子技术有限公司，广州 510070; 2 中国移动通信集团广东有限公司，广州 510623)摘 要 随着5G网络的商用，运营商越来越关注5G网络部署的投资成本。
在5G建网初期，运营商会通过网络规划工具对指定区域进行仿真，最后根据仿真结果制定有效的组网建设方案。
由于射线跟踪算法能很好地对信号的直射、反射、衍射、透射等路径建模，它经常被用来作为精细化仿真的方法。
本文介绍了射线跟踪相关研究进展及算法应用场景，通过实际案例，对两种射线跟踪算法进行研究，分析对比两种射线跟踪算法在5G规划仿真中的应用区别，验证两种算法的可靠性，为未来5G规划组网建设工作提供多种支撑方案。
关键词 5G；射线跟踪；模型校正中图分类号 TN929.5 文献标识码 A 文章编号 1008-5599（2021）04-0027-07收稿日期：2021-02-081 射线跟踪算法简介5G 网络部署场景包括三维楼宇、城区、郊区、山区、高速公路、高铁沿线和工业物联网等，这对5G 技术的网络规划的精度和准确度提出了更高的要求。
要实现准确、高效、常态化的无线网络规划与优化，需要依托精准的无线信道模型和高效的仿真方法。
射线跟踪用于无线通信研究发轫于20世纪90年代，是光学的射线技术在电磁计算领域中的应用，能够准确地考虑到电磁波的各种传播途径，包括直射、反射、绕射和透射等，并考虑到影响电波传播的各种因素，从而针对不同的具体场景做准确的预测。
但它受限于计算复杂度和计算能力，应用复杂度较高。
近来，射线跟踪技术在愈发精细化、智能化的宽带无线通信时代越来越得到关注和认可。
1.1 国内外研究现状射线追踪技术之所以可以服务于大规模真实复杂场景的无线网络规划与优化工作，主要原因在于其具备“准确性”和“高效性”两个特点。
在提升“准确性”方面，射线追踪算法依赖正确的电波传播机理模型，同时还考虑了准确的场景几何参数、材质参数、天线模型以及多种传播机理。
利用最短路径算法进行地震波射线追踪
利用最短路径算法进行地震波射线追踪作者：杨春雨王小磊李栋来源：《环球市场信息导报》2014年第04期射线追踪方法作为一种快速有效的波场近似计算方法，不仅对于地震波理论研究具有重要意义，而且也直接应用于地震波反演及偏移成像等过程。
该文在收集、整理国内外有关研究资料的基础上，着重介绍了最短路径算法，并通过对Marmousi模型的计算，验证了最短路径方法的高精度，及对复杂模型的适应性。
射线追踪的方法种类较多。
传统方法有基于初值问题的打靶法（Shooting method， i.e.，Julian and Gubbins，1977）和基于边值问题的弯曲法（Bending method， i.e.， Um and Thurber， 1987），但是他们不能处理介质中较强的速度变化，有时无法求出全局最小走时，计算效率较低，阴影区内无射线。
随着射线追踪方法的发展，出现了直接从Huygens原理或Fermat原理出发，采用等价波前描述地震波场特征的方法。
Vidale（1988，1990）和Podvin （1990）等人则从程函方程出发，首先求出走时场分布，再计算走时场的最速下降方向的办法，得到每一条接收点到震源的射线路径。
随后，Qin（1992）等人对Vidale的方法作了改进，提出了波前扩展方法。
黃联捷、李幼铭、吴如山（1992）基于Huygens 原理提出WFRT 方法，根据计算精度的要求，逐次细化网格，而求得最小走时。
Sava 和Fomel（1998）提出了HWT（huygencs wavefront tracing）法。
Moser（1991）提出了根据费马原理的最短路径法。
自上世纪八十年代后期发展起来的基于网格单元的射线追踪算法由于其诸多优点，因而倍受人们的青睐。
与传统的射线追踪算法相比而言，基于网格单元的算法具有四大优点：①可利用波振面向外扩展传播的原理一次性计算出速度模型中所有网格节点的射线走时及相应的路径，并能正确的追踪检波器位于射线阴影区的衍射波射线；②算法数值计算稳定，所得到的解总是全局最佳射线路径及相应最小走时；③多炮多道接收时表现得更为高效，精度也比传统射线追踪方法要高；④在连续介质中网格单元算法始终能找到初至波走时，而传统射线方法则只能找出唯一走时，且很难判别这个走时是属于初至波还是属于后续波（De Kool et al，2006）。
电磁波传播中射线追踪技术的应用指南与射线与物体交互计算方法
电磁波传播中射线追踪技术的应用指南与射线与物体交互计算方法摘要：电磁波传播中射线追踪技术是一种常用的分析和模拟电磁波传播的方法。
本文将介绍射线追踪技术的基本原理以及其在不同领域的应用指南。
此外，还将介绍射线与物体交互计算的方法，以实现更精确的仿真结果。
最后，本文将探讨射线追踪技术的未来发展方向和挑战。
1.引言电磁波传播是在现代通信、雷达、无线电频谱管理等领域中至关重要的研究领域。
与传统的计算方法相比，射线追踪技术可以提供更高的计算效率和更准确的结果。
其基本原理是通过追踪电磁波的射线路径，从而评估传播路径中的衰减、反射和散射等特性。
2.射线追踪技术的基本原理射线追踪技术的基本原理是利用几何光学的原理，将传播路径划分为一系列光线的束，通过追踪这些光线的传播路径和相互作用来模拟电磁波传播现象。
射线追踪技术包括以下几个关键步骤：2.1 光线源的确定光线源的确定是射线追踪的第一步。
根据具体问题的需求，光线源可以是点源、线源或面源。
在确定光线源后，需要确定其位置和辐射特性。
2.2 光线的追踪在确定光线来源后，通过解射线方程追踪射线的路径。
其中，射线方程是由Maxwell方程组导出的，可以通过求解微分方程的数值方法来实现。
通过递归追踪，可以获得射线的传播路径和角度。
2.3 射线的相互作用射线在传播过程中会与物体表面发生相互作用，包括反射、折射和散射等。
这些相互作用在射线追踪中起到关键作用，影响射线的传播方向和强度。
3.射线追踪技术在不同领域的应用指南射线追踪技术在各个领域都有着广泛的应用。
以下是几个常见领域的应用指南：3.1 通信系统设计射线追踪技术可用于评估射频信号在室内分布和覆盖范围，以帮助设计无线通信系统。
通过分析射线的衰减和反射路径，可以优化天线摆放位置和功率配置，以实现更好的信号覆盖和性能。
3.2 雷达系统仿真雷达系统中的射线追踪技术可以模拟雷达波束的传播路径和干扰环境。
通过考虑地形和静态或动态散射体的影响，可以评估雷达系统的性能和工作范围。
射线模型Bellhop的并行化处理
ZHANG Chaojin1,2,3 SUN Bingwen1,2
(1 Key Laboratory of Underwater Acoustic Environment, Beijing 100190, China) (2 Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China)
文献标识码: A
文章编号: 1000-310X(2019)01-0001-07
DOI: 10.11684/j.issn.1000-310X.2019.01.001
Parallel computation of sound field based on beam tracing model Bellhop
摘要 射线模型是声场计算时常用的模型之一，为了使射线模型 Bellhop 实现对声场的快速计算，该文基于
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R
E
C\I\S
A
6.2 高斯海山(变化的海底)
• 应用高斯函数生成一个理想化的海山。
行号
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''
不包括波束移位效果（默认）；
S
包括波束移位效果
设置阵列类型；可以空着
OPTION(4:4)
R
点源（圆柱形坐标系）（默认）
X
线源（笛卡尔坐标系）
设置阵列类型；可以空着
OPTION(5:5)
R
直线网格，接收器置于rr(:)×rd(:)点（默认）
I
不规则网格，接收器在rr(:)，rd(:)。
Matlab 脚本
内容
'Munk / Flat / Arrives' 50.0 1 'SVW' 51 0.0 5000.0 0.0 1548.52 / 200.0 1530.29 / 250.0 1526.69 / 400.0 1517.78 / 600.0 1509.49 / 800.0 1504.30 / 1000.0 1501.38 / 1200.0 1500.14 / 1400.0 1500.12 / 1600.0 1501.02 / 1800.0 1502.57 / 2000.0 1504.62 / 2200.0 1507.02 / 2400.0 1509.69 / 2600.0 1512.55 / 2800.0 1515.56 / 3000.0 1518.67 / 3200.0 1521.85 / 3400.0 1525.10 / 3600.0 1528.38 / 3800.0 1531.70 / 4000.0 1535.04 / 4200.0 1538.39 / 4400.0 1541.76 / 4600.0 1545.14 / 4800.0 1548.52 / 5000.0 1551.91 / 'A' 0.0 5000.0 1600.00 0.0 1.8 .0 .0 / 1 1000.0 / 1 1000.0 / 1 101.0 / 'A' 101 -14.0 14.0 / 100.0 5500.0 102.0
• 3、对于每个作业的主程序文件一句一句地消化， 深化理解每份作业的内涵，算是提高。耗时估计3-7 天。
• 4、本文档适合大三以上和非水声物理专业同志们 的快速参学。
声学工具箱的结构
• KRAKEN normal mode approach
• KRAKEN 简正波方法
• BELLHOP Gaussian beam tracing and ray tracing code
OPTIONS3（选项3） 语 法 5个字符的字符串，用于设定输出选项。
说明
设定将写入输出文件的信息类型。
R
生成声线文件
E
生成本征声线文件
OPTION(1:1)
A
生成幅度-延时文件（ascii码）
a
生成幅度-延时文件（二进制）
C
相干TL计算
I
非相干TL计算
S
半相干TL计算（Lloyd镜空着
• SPARC 在时域直接运算 的谱积分程序
BELLHOP .ENV 文件
BELLHOP .ENV 文件
6.1 水平海底波导
flatwav_A.env / Arrives
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说明
TITLE FREQ (Hz) NMEDIA SSP-TOP-WATER-OPT NMESH SIGMA Z(NSSP) Z() CP() CS() RHO() AP() AS() .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . BOTOPT SIGMA ZB CPB CSB RHOB APB ASB NSD SD(1:NSD) (m) NRD RD(1:NRD) (m) NRR RR(1:NRR ) (km) OPTION: 'R/E/C/A/I/S' NBEAMS ISINGLE ALPHA(1:NBEAMS) (°) STEP (m) ZBOX (m) RBOX (km)
G
笛卡尔坐标系中的几何帽形波束（默认）
OPTION(2:2)
g
射线中心坐标系中的几何帽形波束
C
采用笛卡尔坐标系Cerveny高斯波束
R
采用中心射线坐标系Cerveny高斯波束
B
几何高斯波束
设定波束移位效果等选项；可以空着
*
读取声源波束模式*.sbp（角度-幅度）文件
OPTION(3:3)
O
不读取（默认）
• BELLHOP 高斯波束追踪 与射线追踪程序
• SCOOTER spectral integral (also know as wavenumber integration or the reflectivity method)
• SCOOTER 谱积分(也称为 波数积分或反射率法)
• SPARC A spectral integral code that operates directly in the time domain.
Bellhop射线追踪程序概述
招式说明：
• 1、在64位windows平台上，将本程序包的文件夹 添加在matlab“设置路径”的“添加并包含子文件 夹”。
• 2、读完文档，跑完本程序包所有招式（作业）， 射线追踪算法的运行就算初步通关，对于海洋传播 声场的二维射线表达方法基本上建立感性认识。单 单溜达作业（六路招式）耗时半天。