[[Image:Splash-prop.jpg|right|750px720px]]<strong><font color="#4e1985" size="4">True 3D, Coherent, Polarimetric Ray Tracer That Simulates Very Large Urban Scenes In Just Few Minutes!</font></strong><table><tr><td>[[image:Cube-icon.png | link=Getting_Started_with_EM.Cube]] [[image:cad-ico.png | link=Building_Geometrical_Constructions_in_CubeCAD]] [[image:fdtd-ico.png | link= An EM.Tempo]] [[image:static-ico.png | link=EM.Ferma]] [[image:planar-ico.png | link=EM.Picasso]] [[image:metal-ico.png | link=EM.Libera]] [[image:po-ico.png | link=EM.Illumina]]</td><tr></table>[[Image:Tutorial_icon.png|30px]] '''[[EM.Cube#EM.Terrano_Documentation | EM.Terrano Primer Tutorial Gateway]]'''Â [[Image:Back_icon.png|30px]] '''[[EM.Cube | Back to EM.Cube Main Page]]'''==Product Overview==
===EM.Terrano in a Nutshell ===
EM.Terrano is a physics-based, site-specific, wave propagation modeling tool that enables engineers to quickly determine how radio waves propagate in urban, natural or mixed environments. EM.Terrano's simulation engine is equipped with a fully polarimetric, coherent 3D ray tracing solver based on the Shooting-and-Bouncing-Rays (SBR) method, which utilizes geometrical optics (GO) in combination with uniform theory of diffraction (UTD) models of building edges. EM.Terrano lets you analyze and resolve all the rays transmitted from one ore more signal sources, which propagate in a real physical site channel made up of buildings, terrain and other obstructing structures. EM.Terrano finds all the rays received by a receiver at a particular location in the physical site and computes their vectorial field and power levels, time delays, angles of arrivaland departure, etc. Using EM.Terrano you can examine the connectivity of a communication link between any two points in a real specific propagation site.
{{Note|Since its introduction in 2002, EM.Terrano is has helped wireless engineers around the globe model the physical channel and the mechanisms by which radio signals propagate in various environments. EM.Terranoâs advanced ray tracing '''[[Propagation Module]]''' of '''[[EMsimulator finds the dominant propagation paths at each specific physical site.Cube]]''', It calculates the true signal characteristics at the actual locations using physical databases of the buildings and terrain at a comprehensivegiven site, integrated, modular electromagnetic modeling not those of a statistically average or representative environment. The earlier versions of EM.Teranno shares Terrano's SBR solver relied on certain assumptions and approximations such as the visual interfacevertical plane launch (VPL) method or 2.5D analysis of urban canyons with prismatic buildings using two separate vertical and horizontal polarizations. In 2014, we introduced a new fully 3D polarimetric SBR solver that accurately traces all the three X, Y and Z components of the electric fields (both amplitude and phase) at every point inside the computational domain. Using a 3D parametric CAD modeler, data visualization toolsyou can now set up any number of buildings with arbitrary geometries, no longer limited to vertical prismatic shapes. Versatile interior wall arrangements allow indoor propagation modeling inside complex building configurations. The most significant recent development is a multicore parallelized SBR simulation engine that takes advantage of ultrafast k-d tree algorithms borrowed from the field of computer graphics and many more utilities video gaming to achieve the ultimate speed and features collectively known as '''[[CubeCAD]]''' with all of [[EM.Cube]]'s other computational modulesefficiency in geometrical optics ray tracing.}}
[[Image:Info_icon.png|40px30px]] Click here to learn more about the '''[[Getting_Started_with_EM.CUBE Basic Principles of SBR Ray Tracing | EM.Cube Modeling EnvironmentBasic SBR Theory]]'''.
<table><tr><td> [[Image:Info_iconManhattan1.png|40pxthumb|left|420px|A large urban propagation scene featuring lower Manhattan.]] Click here to learn more about the basic functionality of '''[[CubeCAD]]'''.</td></tr></table>
=== Physics-Based EM.Terrano as the Propagation Channel Modeling Using SBR Ray Tracing Module of EM.Cube ===
Every wireless communication system involves a transmitter that transmits some sort EM.Terrano is the ray tracing '''Propagation Module''' of signal (voice'''[[EM.Cube]]''', videoa comprehensive, dataintegrated, etcmodular electromagnetic modeling environment.), a receiver that receives and detects EM.Terrano shares the transmitted signalvisual interface, 3D parametric CAD modeler, data visualization tools, and a channel in which the signal is transmitted into the air many more utilities and travels from the location features collectively known as [[Building_Geometrical_Constructions_in_CubeCAD | CubeCAD]] with all of the transmitter to the location of the receiver[[EM. The channel is the physical medium in which the electromagnetic waves propagate. The successful design of a communication system depends on an accurate link budget analysis that determines whether the receiver receives adequate signal power to detect it against the background noise. The simplest channel is the free space. In a free-space line-of-sight (LOS) communication system, the signal propagates directly from the transmitter to the receiver without encountering any obstacles (scatterers). Free-space line-of-sight channels are ideal scenarios that can typically be used to model aerial or space communication system applicationsCube]]'s other computational modules.
With the seamless integration of EM.Terrano with [[Image:Info_iconEM.png|40pxCube]] Click here 's other modules, you can now model complex antenna systems in [[EM.Tempo]], [[EM.Libera]], [[EM.Picasso]] or [[EM.Illumina]], and generate antenna radiation patterns that can be used to learn more about model directional transmitters and receivers at the theory two ends of your propagation channel. Conversely, you can analyze a '''propagation scene in EM.Terrano, collect all the rays received at a certain receiver location and import them as coherent plane wave sources to [[Maxwell%27s_Equations#Free-Space_Wave_Propagation | Free-Space Propagation ChannelEM.Tempo]], [[EM.Libera]], [[EM.Picasso]] or [[EM.Illumina]]'''.
Real communication channels, however, are more complicated and involve a large number of wave scatterers[[Image:Info_icon. For example, in an urban environment, the obstructing buildings, vehicles and vegetation reflect, diffract or attenuate the propagating radio waves. As a result, the receiver receives a distorted signal that contains several components with different power levels and different time delays arriving from different angles. The different rays arriving at a receiver location create constructive and destructive interference patterns. This is known as the multipath effect. This together with the shadowing effects caused by building obstructions lead png|30px]] Click here to channel fadinglearn more about '''[[Getting_Started_with_EM. The use of statistical models for prediction of fading effects is widely popular among communication system designers. These models are either based on measurement data or derived from simplistic analytical frameworks. The statistical models often exhibit considerable errors especially in areas having mixed building sizes. In such cases, one needs to perform a physics-based, site-specific analysis of the propagation environment to accurately identify and establish all the possible signal paths from the transmitter to the receiverCube | EM. This involves an electromagnetic analysis of the scene with all of its geometrical and physical detailsCube Modeling Environment]]'''.
[[Image:multi1_tn.png|thumb|500px|A multipath propagation scene showing all the rays arriving at a particular receiver.]]Link budget analysis for a multipath channel is a challenging task due to the large size === Advantages & Limitations of the computational domains involvedEM. Typical propagation scenes usually involve length scales on the order of thousands of wavelengths. To calculate the path loss between the transmitter and receiver, one must solve [[MaxwellTerrano's Equations|Maxwell's equations]] in an extremely large space. Full-wave numerical techniques like the Finite Difference Time Domain (FDTD) method, which require a fine discretization of the computational domain, are therefore impractical for solving large-scale propagation problems. The practical solution is to use asymptotic techniques such as SBR, which utilize analytical techniques over large distances rather than a brute force discretization of the entire computational domain. Such asymptotic techniques, of course, have to compromise modeling accuracy for computational efficiency.Solver ===
EM.Terrano provides 's SBR simulation engine utilizes an asymptotic intelligent ray tracing simulation engine algorithm that is based on a technique known as Shootingthe concept of k-anddimensional trees. A k-Bouncingd tree is a space-Rays (SBR)partitioning data structure for organizing points in a k-dimensional space. In this technique, propagating spherical waves k-d trees are modeled as ray tubes or beams particularly useful for searches that emanate from involve multidimensional search keys such as range searches and nearest neighbor searches. In a sourcetypical large radio propagation scene, travel in space, bounce there might be a large number of rays emanating from obstacles and are collected by the receivertransmitter that may never hit any obstacles. As For example, upward-looking rays propagate away from in an urban propagation scene quickly exit the computational domain. Rays that hit obstacles on their source (transmitter)path, they begin to spread (or diverge) over distance. In on the other wordshand, the cross section or footprint of a ray tube expands as a function of the distance from the source. EMgenerate new reflected and transmitted rays.Terrano uses an accurate equiThe k-angular ray generation scheme to that produces almost identical ray tubes in d tree algorithm traces all directions to satisfy energy these rays systematically in a very fast and power conservation requirementsefficient manner. Another major advantage of k-d trees is the fast processing of multi-transmitters scenes.
When EM.Terrano performs fully polarimetric and coherent SBR simulations with arbitrary transmitter antenna patterns. Its SBR simulation engine is a true asymptotic "field" solver. The amplitudes and phases of all the three vectorial field components are computed, analyzed and preserved throughout the entire ray hits an obstructing surfacetracing process from the source location to the field observation points. You can visualize the magnitude and phase of all six electric and magnetic field components at any point in the computational domain. In most scenes, the buildings and the ground or terrain can be assumed to be made of homogeneous materials. These are represented by their electrical properties such as permittivity ε<sub>r</sub> and electric conductivity σ. More complex scenes may involve a multilayer ground or multilayer building walls. In such cases, one can no longer use the simple reflection or more transmission coefficient formulas for homogeneous medium interfaces. EM.Terrano calculates the reflection and transmission coefficients of multilayer structures as functions of incident angle, frequency and polarization and uses them at the following phenomena may happen:respective specular points.
# Reflection from It is very important to keep in mind that SBR is an asymptotic electromagnetic analysis technique that is based on Geometrical Optics (GO) and the locally flat surface# Transmission through the locally flat surface# Uniform Theory of Diffraction (UTD). It is not a "full-wave" technique, and it does not provide a direct numerical solution of Maxwell's equations. SBR makes a number of assumptions, chief among them, a very high operational frequency such that the length scales involved are much larger than the operating wavelength. Under this assumed regime, electromagnetic waves start to behave like optical rays. Virtually all the calculations in SBR are based on far field approximations. In order to maintain a high computational speed for urban propagation problems, EM.Terrano ignores double diffractions. Diffractions from edges give rise to a large number of new secondary rays. The power of diffracted rays drops much faster than reflected rays. In other words, an edge between two conjoined locally flat surfaces-diffracted ray does not diffract again from another edge in EM.Terrano. However, reflected and penetrated rays do get diffracted from edges just as rays emanated directly from the sources do.
<table><tr><td> [[Image:Info_iconMultipath_Rays.png|40px]] Click here to learn more about thumb|left|500px|A multipath urban propagation scene showing all the theory of '''[[SBR Methodrays collected by a receiver.]]'''.</td></tr></table>
=== Advantages & Limitations of EM.Terrano's SBR Solver =Features at a Glance ==
EM.Terrano's SBR simulation engine utilizes an intelligent ray tracing algorithm that is based on the concept of k-dimensional trees. A k-d tree is a space-partitioning data structure for organizing points in a k-dimensional space. k-d trees are particularly useful for searches that involve multidimensional search keys such as range searches and nearest neighbor searches. In a typical large radio propagation scene, there might be a large number of rays emanating from the transmitter that may never hit any obstacles. For example, upward-looking rays in an urban propagation scene quickly exit the computational domain. Rays that hit obstacles on their path, on the other hand, generate new reflected and transmitted rays. The k-d tree algorithm traces all these rays systematically in a very fast and efficient manner. Another major advantage of k-d trees is the fast processing of multi-transmitters scenes. === Scene Definition / Construction ===
EM.Terrano performs fully polarimetric <ul> <li> Buildings/blocks with arbitrary geometries and coherent SBR simulations material properties</li> <li> Buildings/blocks with impenetrable surfaces or penetrable surfaces using thin wall approximation</li> <li> Multilayer walls for indoor propagation scenes</li> <li> Penetrable volume blocks with arbitrary transmitter antenna patterns. Its SBR simulation engine is a true asymptotic "field" solver. The amplitudes geometries and phases material properties</li> <li> Import of all the three vectorial field components are computedshapefiles and STEP, analyzed IGES and preserved throughout the entire ray tracing process from the source location to the field observation points. You can visualize the magnitude STL CAD model files for scene construction</li> <li> Terrain surfaces with arbitrary geometries and phase of all six electric material properties and magnetic field components at any point in the computational domain. In most scenesrandom rough surface profiles</li> <li> Import of digital elevation map (DEM) terrain models</li> <li> Python-based random city wizard with randomized building locations, the extents and orientations</li> <li> Python-based wizards for generation of parameterized multi-story office buildings and the ground or several terrain can be assumed to be made of homogeneous materials. These are represented by their electrical properties such as permittivity εscene types<sub/li>r </subli> Standard half-wave dipole transmitters and electric conductivity σ. More complex scenes may involve a multilayer ground or multilayer building walls. In such cases, one can no longer use receivers oriented along the simple reflection principal axes</li> <li> Short Hertzian dipole sources with arbitrary orientation</li> <li> Isotropic receivers or transmission coefficient formulas receiver grids for homogeneous medium interfaces. EM.Terrano calculates the reflection and transmission coefficients wireless coverage modeling</li> <li> Radiator sets with 3D directional antenna patterns (imported from other modules or external files)</li> <li> Full three-axis rotation of multilayer structures as functions imported antenna patterns</li> <li> Interchangeable radiator-based definition of incident angle, frequency transmitters and polarization and uses them at the respective specular points. receivers (networks of transceivers)</li></ul>
It is very important to keep in mind that SBR is an asymptotic electromagnetic analysis technique that is based on Geometrical Optics (GO) and the Uniform Theory of Diffraction (UTD). It is not a "full-wave" technique, and it does not provide a direct numerical solution of [[Maxwell's Equations|Maxwell's equations]]. SBR makes a number of assumptions, chief among them, a very high operational frequency such that the length scales involved are much larger than the operating wavelength. Under this assumed regime, electromagnetic waves start to behave like optical rays. Virtually all the calculations in SBR are based on far field approximations. In order to maintain a high computational speed for urban propagation problems, EM.Terrano ignores double diffractions. Diffractions from edges give rise to a large number of new secondary rays. The power of diffracted rays drops much faster than reflected rays. In other words, an edge-diffracted ray does not diffract again from another edge in EM.Terrano. However, reflected and penetrated rays do get diffracted from edges just as rays emanated directly from the sources do.=== Wave Propagation Modeling ===
[[Image:PROP14<ul> <li> Fully 3D polarimetric and coherent Shoot-and-Bounce-Rays (1SBR).png|thumb|250px|The Navigation Tree simulation engine</li> <li> GTD/UTD diffraction models for diffraction from building edges and terrain</li> <li> Triangular surface mesh generator for discretization of EM.Terrano]]arbitrary block geometries</li> <li> Super-fast geometrical/optical ray tracing using advanced k-d tree algorithms</li> <li> Intelligent ray tracing with user defined angular extents and resolution</li> <li> Ray reflection, edge diffraction and ray transmission through multilayer walls and material volumes</li> <li> Communication link analysis for superheterodyne transmitters and receivers</li> <li> 17 digital modulation waveforms for the calculation of E<sub>b</sub>/N<sub>0</sub> and Bit error rate (BER)</li> <li> Incredibly fast frequency sweeps of the entire propagation scene in a single SBR simulation run</li> <li> Parametric sweeps of scene elements like building properties, or radiator heights and rotation angles</li> <li> Statistical analysis of the propagation scene</li> <li> Polarimetric channel characterization for MIMO analysis</li> <li> "Almost real-time" Polarimatrix solver using an existing ray database</li> <li> "Almost real-time" transmitter sweep using the Polarimatrix solver</li> <li> "Almost real-time" rotational sweep for modeling beam steering using the Polarimatrix solver</li> <li> "Almost real-time" mobile sweep for modeling mobile communications between Tx-Rx pairs along a mobile path using the Polarimatrix solver</li></ul>
=== Data Generation & Visualization ===Â <ul> <li> Standard output parameters for received power, path loss, SNR, E<sub>b</sub>/N<sub>0</sub> and BER at each individual receiver</li> <li> Graphical visualization of propagating rays in the scene</li> <li> Received power coverage maps</li> <li> Link connectivity maps (based on minimum required SNR and BER)</li> <li> Color-coded intensity plots of polarimetric electric field distributions</li> <li> Incoming ray data analysis at each receiver including delay, angles of arrival and departure</li> <li> Cartesian plots of path loss along defined paths</li> <li> Power delay profile of the selected receiver</li> <li> Polar stem charts of angles of arrival and departure of the selected receiver</li></ul>Â == Building a Propagation Scene in EM.Terrano ==
=== The Various Elements of a Propagation Scene ===
A typical propagation scene in EM.Terrano consists of several elements. At a minimum, you need a transmitter (Tx) at some location to launch rays into the scene and a receiver (Rx) at another location to receive and collect the incoming rays. A transmitter and a receiver together make the simplest propagation scene, representing a free-space line-of-sight (LOS) channel. A transmitter is one of In EM.Terrano's several , a transmitter represents a point source types, while a receiver is one of EM.Terrano's several represents a point observable types. A simpler source type is Both a Hertzian dipole representing an almost omni-directional radiator. A simpler observable is transmitter and a field sensor that is used to compute receiver are associated with point objects, which are one of the electric many types of geometric objects you can draw in the project workspace. Your scene might involve more than one transmitter and magnetic fields on possibly a specified planelarge grid of receivers.
An outdoor A more complicated propagation scene may involve usually contains several buildings modeled by impenetrable surfaces and an underlying flat ground or irregular terrain surface. An indoor propagation scene may involve several , walls modeled by thin penetrable surfaces, a ceiling or other kinds of scatterers and a floor arranged according to a certain building layoutwave obstructing objects. You can also build mixed scenes involving both impenetrable and penetrable blocks. Your sources and observables can be placed anywhere model all of these elements by drawing geometric objects in the scene. Your transmitters and receivers can be placed outdoors project workspace or indoorsby importing external CAD models. A complete list EM.Terrano does not organize the geometric objects of your project workspace by their material composition. Rather, it groups the various elements of geometric objects into blocks based on a propagation scene is given in the '''Physical Structure''' section common type of interaction with incident rays. EM.Terrano's Navigation Tree as followsoffer the following types of object blocks:
* '''{| class="wikitable"|-! scope="col"| Icon! scope="col"| Block/Group Type ! scope="col"| Ray Interaction Type! scope="col"| Object Types Allowed! scope="col"| Notes|-| style="width:30px;" | [[Block_TypesFile:impenet_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Impenetrable_Surfaces_for_Outdoor_ScenesImpenetrable Surface |Impenetrable SurfacesSurface]]'''| style="width: feature 200px;" | Ray reflection and , ray diffraction of impinging rays. Rays hit the facets of this type of blocks and bounce back| style="width:250px;" | All solid & surface geometric objects, but they do not penetrate the object. It is assumed that the interior of such blocks or buildings are highly absorptiveno curve objects| style="width:300px;" | Basic building group for outdoor scenes|-| style="width:30px;" | [[File:penet_surf_group_icon.png]]* '''| style="width:150px;" | [[Block_TypesGlossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Penetrable_Surfaces_for_Indoor_ScenesPenetrable Surface |Penetrable SurfacesSurface]]'''| style="width: feature 200px;" | Ray reflection, ray diffraction, ray transmission in free space| style="width:250px;" | All solid & surface geometric objects, no curve objects| style="width:300px;" | Behaves similar to impenetrable surface and diffraction of impinging rays. These blocks represent uses thin surfaces that are wall approximation for generating transmitted rays, used to model the exterior and interior walls of hollow buildings. Rays reflect off the surface of penetrable surfaces with ray penetration, entry and diffract off their edges. They also penetrate the thin surface and continue their path in the free space on the other side of the wallexit |-| style="width:30px;" | [[File:terrain_group_icon.png]]* '''| style="width:150px;" | [[Block_Types#Using_Terrain_Surfaces_vsGlossary of EM._Global_Ground Cube's Materials, Sources, Devices & Other Physical Object Types#Terrain Surface | Terrain SurfacesSurface]]'''| style="width: feature 200px;" | Ray reflection and optional , ray diffraction of impinging rays. These blocks are used to provide one | style="width:250px;" | All surface geometric objects, no solid or more curve objects | style="width:300px;" | Behaves exactly like impenetrable, ground surfaces for surface but can change the propagation scene. Rays simply bounce off terrain objectselevation of all the buildings and transmitters and receivers located above it|-| style="width:30px;" | [[File:penet_vol_group_icon. png]]* '''| style="width:150px;" | [[Block_TypesGlossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Penetrable_VolumesPenetrable Volume |Penetrable VolumesVolume]]'''| style="width: feature 200px;" | Ray reflection, ray diffraction, ray transmission and diffraction of impinging rays. These blocks are used ray attenuation inside homogeneous material media| style="width:250px;" | All solid geometric objects, no surface or curve objects| style="width:300px;" | Used to model wave propagation inside general a volumetric material media or special environments such as fogblock, rain also used for creating individual solid walls and vegetationinterior building partitions and panels in indoor scenes|-| style="width:30px;" | [[File:base_group_icon.png]]* '''| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Defining_Base_Point_SetsBase Location Set |Base PointsLocation Set]]'''| style="width: are used to locate a single transmitter or receiver 200px;" | Either ray generation or arrays ray reception| style="width:250px;" | Only point objects| style="width:300px;" | Required for the definition of transmitters or and receivers in |-| style="width:30px;" | [[File:scatterer_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Point Scatterer Set | Point Scatterer Set]]| style="width:200px;" | Ray reception and ray scattering| style="width:250px;" | Only point, box and sphere objects| style="width:300px;" | Required for the scenedefinition of point scatterers as targets in a radar simulation |-| style="width:30px;" | [[File:Virt_group_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Virtual_Object_Group | Virtual Object]]| style="width:200px;" | No ray interaction| style="width:250px;" | All types of objects| style="width:300px;" | Used for representing non-physical items |}
[[Image:Info_icon.png|40px]] Click here on each type to learn more about '''it in the [[Block Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types]]'''.
In EM.TerranoImpenetrable surfaces, the various scene elements like buildingspenetrable surfaces, terrain objects surfaces and base points are grouped together based on their type. All penetrable volumes represent all the objects listed under a particular group that obstruct the propagation of electromagnetic waves (rays) in the navigation tree share the same color, texture and material propertiesfree space. Once a new block group has been created in What differentiates them is the navigation tree, it becomes the "Active" group types of physical phenomena that are used to model their interaction with the project workspace, which is always displayed in bold lettersimpinging rays. You can start drawing new EM.Terrano discretizes geometric objects under the active nodeinto a number of flat facets. Any block group can be made active by right-clicking on its name in The field intensity, phase and power of the navigation tree reflected and selecting transmitted rays depend on the '''Activate''' item material properties of the contextual menuobstructing facet. The specular surface of a facet can be modeled locally as a simple homogeneous dielectric half-space or as a multilayer medium. In that respect, all the obstructing objects such as buildings, walls, terrain, etc. behave in a similar way:
* They terminate an impinging ray and replace it with one or more new rays.* They represent a specular interface between two media of different material compositions for calculating the reflection, transmission or diffraction coefficients. An outdoor propagation scene typically involves several buildings modeled by impenetrable surfaces. Rays hit the facets of impenetrable buildings and bounce back, but they do not penetrate the object. It is assumed that the interior of such buildings are highly dissipative due to wave absorption or diffusion. An indoor propagation scene typically involves several walls, a ceiling and a floor arranged according to a certain building layout. Penetrable surfaces are used to model the exterior and interior walls of buildings. Rays reflect off these surfaces and diffract off their edges. They also penetrate the thin surface and continue their path in the free space on the other side of the wall. Terrain surfaces with irregular shapes or possibly random rough surfaces are used as an alternative to the flat global ground. You can also build mixed scenes involving both impenetrable and penetrable blocks or irregular terrain. In the context of a propagation scene, penetrable volumes are often used to model block of rain, fog or vegetation. Base location sets are used to geometrically represent point transmitters and point receivers in the project workspace. Sometimes it is helpful to draw graphical objects as visual clues in the project workspace. These non-physical objects must belong to a virtual object group. Virtual objects are not discretized by EM.Terrano's mesh generator, and they are not passed onto the input data files of the SBR simulation engine.  <table><tr><td> [[Image:PROP MAN2.png|thumb|left|720px|An urban propagation scene generated by EM.Terrano's "Random City" and "Basic Link" wizards. It consists of 25 cubic brick buildings, one transmitter and a large two-dimensional array of receivers. ]]</td></tr></table> === Organizing the Propagation Scene by Block Groups === In EM.Terrano, all the geometric objects associated with the various scene elements like buildings, terrain surfaces and base location points are grouped together as blocks based on their common type. All the objects listed under a particular group in the navigation tree share the same color, texture and material properties. Once a new block group has been created in the navigation tree, it becomes the "Active" group of the project workspace, which is always displayed in bold letters. You can draw new objects under the active node. Any block group can be made active by right-clicking on its name in the navigation tree and selecting the '''Activate''' item of the contextual menu.  <table><tr><td> [[Image:PROP MAN1.png|thumb|left|480px|EM.Terrano's navigation tree.]]</td></tr></table> It is recommended that you first create block groups, and then draw new objects under the active block group. However, if you start a new EM.Terrano project from scratch, and start drawing a new object without having previously defined any block groups, a new default impenetrable surface group is created and added to the navigation tree to hold your new CAD object. You can always change the properties of a block group later by accessing its property dialog from the contextual menu. You can also delete a block group with all of its objects at any time. {{Note|You can only import external CAD models (STEP, IGES, STL, DEM, etc.) only to the CubeCAD module. You can then transfer the imported objects from CubeCAD to EM.Terrano.}} === Moving Objects Among Different Block Groups === You can move any geometric object or a selection of objects from one block group to another. You can also transfer objects among [[EM.Cube]]'s different modules. For example, you often need to move imported CAD models of terrain or buildings from CubeCAD to EM.Terrano. To transfer objects, first select them in the project workspace or select their names in the navigation tree. Then right-click on them and select <b>Move To → Module Name → Object Group</b> from the contextual menu. For example, if you want to move a selected object to a block group called "Terrain_1" in EM.Terrano, then you have to select the menu item '''Move To → EM.Terrano → Terrain_1''' as shown in the figure below. Note that you can transfer several objects altogether using the keyboards's {{key|Ctrl}} or {{key|Shift}} keys to make multiple selections.  <table><tr><td> [[Image:PROP MAN3.png|thumb|left|720px|Moving the terrain model of Mount Whitney originally imported from an external digital elevation map (DEM) file to EM.Terrano.]]</td></tr><tr><td>[[Image:PROP MAN4.png|thumb|left|720px|The imported terrain model of Mount Whitney shown in EM.Terrano's project workspace under a terrain group called "Terrain_1".]]</td></tr></table> === Adjustment of Block Elevation on Underlying Terrain Surfaces === In EM.Terrano, buildings and all other geometric objects are initially drawn on the XY plane. In other words, the Z-coordinates of the local coordinate system (LCS) of all blocks are set to zero until you change them. Since the global ground is located a z = 0, your buildings are seated on the ground. When your propagation scene has an irregular terrain, you would want to place your buildings on the surface of the terrain and not buried under it. This can be done automatically as part of the definition of the block group. Open the property dialog of a block group and check the box labeled '''Adjust Block to Terrain Elevation'''. All the objects belonging to that block are automatically elevated in the Z direction such that their bases sit on the surface of their underlying terrain. In effect, the LCS of each of these individual objects is translated along the global Z-axis by the amount of the Z-elevation of the terrain object at the location of the LCS.  {{Note| You have to make sure that the resolution of your terrain, its variation scale and building dimensions are all comparable. Otherwise, on a rapidly varying high-resolution terrain, you will have buildings whose bottoms touch the terrain only at a few points and parts of them hang in the air.}} <table><tr><td> [[Image:PROP MAN5.png|thumb|left|480px|The property dialog of impenetrable surface showing the terrain elevation adjustment box checked.]]</td></tr></table> <table><tr><td> [[Image:PROP MAN6.png|thumb|left|360px|A set of buildings on an undulating terrain without elevation adjustment.]]</td><td>[[Image:PROP MAN7.png|thumb|left|360px|The set of buildings on the undulating terrain after elevation adjustment.]]</td></tr></table>
[[Image:PROP15.png|thumb|400px|== EM.Terrano's Ray Domain Settings dialog.]][[Image:PROP4.png|thumb|400px|EM.Terrano's & Global Ground Settings dialog.]]Environment ==
=== Why Do You Need a Finite Computational Domain? ===
* Open the Ray Domain Settings Dialog by clicking the '''Domain''' [[File:image025.jpg]] button of the '''Simulate Toolbar''', or by selecting '''Menu > Simulate > Computational Domain > Settings...''', or by right-clicking on the '''Ray Domain''' item of the navigation tree and selecting '''Domain Settings...''' from the contextual menu, or simply using the keyboard shortcut {{key|Ctrl+A}}.
* The size of the Ray domain is specified in terms of six '''Offset''' [[parameters]] along the ±X, ±Y and ±Z directions. The default value of all these six offset [[parameters]] is 10 project units. Change these values as you like.
* You can also change the color of the domain box using the {{key|Color}} button.
* After changing the settings, use the {{key|Apply}} button to make the changes effective while the dialog is still open.
Â
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[[Image:PROP15.png|thumb|left|480px|EM.Terrano's domain settings dialog.]]
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</table>
=== Understanding the Global Ground ===
Most outdoor and indoor propagation scenes include a flat ground at their bottom, which bounces incident rays back into the scene. EM.Terrano provides a global flat ground at z = 0. The global ground indeed acts as an impenetrable surface that blocks the entire computational domain from the z = 0 plane downward. It is displayed as a translucent green plane at z = 0 extending downward. The color of the ground plane is always the same as the color of the ray domain. The global ground is assumed to be made of a homogeneous dielectric material with a specified permittivity ε<sub>r</sub> and electric conductivity σ. By default, a rocky ground is assumed with ε<sub>r</sub> = 5 and σ = 0.005 S/m. You can remove the global ground, in which case, you will have a free space scene. To disable the global ground, open up the "Global Ground Settings" dialog, which can be accessed by right clicking on the '''Global Ground''' item in the Navigation Tree and selecting '''Global Ground Settings... '''Remove the check mark from the box labeled '''"Include Half-Space Ground (z<0)"''' to disable the global ground. This will also remove the green translucent plane from the bottom of your scene. You can also change the material properties of the global ground and set new values for the permittivity and electric conductivity of the impenetrable, half-space, dielectric medium.
Alternatively, you can use EM.Terrano's '''Empirical Soil Model''' to define the material properties of the global ground. This model requires a number of [[parameters]]: Temperature in °C, and Volumetric Water Content, Sand Content and Clay Content all as percentage.
{{Note|To model a free-space propagation scene, you have to disable EM.Terrano's default global ground.}}
=== Buildings, Terrain & Obstructing Blocks ===<table><tr><td> [[Image:Global environ.png|thumb|left|720px|EM.Terrano's Global Environment Settings dialog.]]</td></tr></table>
Impenetrable, penetrable and terrain surfaces and penetrable volumes represent buildings, blocks or objects that obstruct the propagation of electromagnetic waves (rays) in the free space. What differentiates them is the types of physical phenomena that are used to model their interaction with the impinging rays. The field intensity, phase and power of the reflected and transmitted rays depend on the material properties of the obstructing surface. The specular surface can be modeled as a simple homogeneous dielectric half-space or as a multilayer structure. In that respect, the buildings, walls, terrain or even the global ground all behave in a similar way:== Defining Point Transmitters & Point Receivers for Your Propagation Scene ==
* They terminate an impinging ray and replace it with one or more new rays.* They represent a specular interface between two media === The Nature of different material compositions for calculating the reflection, transmission and possibly diffraction coefficients.Transmitters & Receivers ===
[[In EM.Terrano]] has generalized , transmitters and receivers are indeed point radiators used for transmitting and receiving signals at different locations of the concept propagation scene. From a geometric point of '''Block''' as any object that obstructs view, both transmitters and affects radio wave propagationreceivers are represented by point objects or point arrays. The following table summarized These are grouped as base locations in the "Physical Structure" section of the navigation tree. As radiators, transmitters and receivers are defined by a radiator type with a certain far-field radiation pattern. Consistent with [[Block Types|block typesEM.Cube]]: 's other computational modules, transmitters are categorizes as an excitation source, while receivers are categorized as a project observable. In other words, a transmitter is used to generate electromagnetic waves that propagate in the physical scene. A receiver, on the other hand, is used to compute the received fields and received signal power or signal-to-noise ratio (SNR). For this reason, transmitters are defined and listed under the "Sources" sections of the navigation tree, while receivers are defined and listed under the "Observables" section.
{| class="wikitable"|-! scope="col"| Block Type! scope="col"|Physical Effects! scope="col"|Legitimate Object Types|-| Impenetrable Surface| Reflection, Diffraction| All solid & surface CAD objects|-| Penetrable Volume| Reflection, Diffraction, Material Medium Transmission| All solid CAD objects|-| Penetrable Surface| Reflection, Diffraction, Thin-Wall Transmission| All solid & surface CAD objects|-| Terrain Surface| Reflection| Specially created tessellated objects only |}EM.Terrano provides three radiator types for point transmitter sets:
[[Image:Info_icon.png|40px]] Click here to learn more about all #Half-wave dipole oriented along one of the different '''[[Block Types]]''' in EM.Terrano.three principal axes#Two collocated, orthogonally polarized, isotropic radiators #User defined (arbitrary) antenna with imported far-field radiation pattern
[[ImageEM.Terrano also provides three radiator types for point receiver sets:prop_manual-12_tn.png|thumb|500px|An imported external terrain model.]]
{{Note|Except for external terrain models, you can import other external objects #Half-wave dipole oriented along one of the three principal axes#Polarization-matched isotropic radiator#User defined (STEP, IGES, STL, etc.arbitrary) only to '''[[CubeCAD]]'''. From [[CubeCAD]], you can then move the antenna with imported objects to EM.Terrano.}}far-field radiation pattern
[[Image:Info_icon.png|40px]] Click here for a general discussion of '''[[Defining Materials in EM.Cube]]'''The default transmitter and receiver radiator types are both vertical (Z-directed) half-wave dipoles.
=== Defining Base Point Sets ===There are three different ways to define a transmitter set or a receiver set:
[[File:PROP1.png|thumb|300px|[[Propagation Module]]'s Base Set dialog]]EM.Terrano uses '''Point''' *By defining point objects to position transmitters and receiver in the propagation scene. Points are regular CAD objects that can be moved around (translated) in the project workspace. The or point objects that are used to represent the transmitters and receivers are grouped together and organized as '''Base Sets''' arrays under physical base location sets in the "Physical Structure" section of the navigation tree. When you move the point objects and then associating them with a transmitter or change their coordinatesreceiver set*Using Python commands emag_tx, all of their associated transmitters or receivers immediately follow them to the new location. For exampleemag_rx, emag_tx_array, you can define a grid of receivers using a base set that is made up of a uniformly spaced array of points emag_rx_array, emag_tx_line and spread them in your scene. You can easily interchange emag_rx_line*Using the role of transmitters and receivers in a scene by switching their associated bases. The usefulness of concept of base sets will become apparent later when we discuss placement of transmitters or receivers on an irregular terrain and adjustment of their elevation. "Basic Link" wizard
To create === Defining a new base set, follow these steps;Point Transmitter Set in the Formal Way ===
* Right-click on the '''Base Sets''' item of navigation tree and select '''Insert Base Set..Transmitters act as sources in a propagation scene.''' A dialog for setting up the Base Set properties opens up.* Enter transmitter is a name for point radiator with a fully polarimetric radiation pattern defined over the base set and change entire 3D space in the default blue color if standard spherical coordinate system. EM.Terrano gives you wish. It is useful to differentiate three options for the base sets radiator associated with transmitters and receivers by their color.* Click the {{key|OK}} button to close the Base Set Dialog.a point transmitter:
Once a base set node has been added to the navigation tree, it becomes the active node for drawing new objects. Under base sets, you can only draw point objects. All other object creation tools are disabled. A point is initially drawn on the XY plane. Make sure to change the Z* Half-coordinate of your point, otherwise, your radiator will fall on the global ground at z = 0. You can also create arrays of base points under the same base set. This is particularly useful for setting up receiver grids to compute coverage maps. Simply select a point object and click the '''Array Tool''' of '''Tools Toolbar''' or use the keyboard shortcut "A". Enter values for the X, Y or Z spacing as well as the number of elements along these three directions in the Array Dialog. In most propagation scenes you are interested in 2D horizontal arrays along a fixed Z coordinate (parallel to the XY plane).wave dipole* Orthogonally polarized isotropic radiators* User defined antenna pattern
== Defining Sources & Observables By default, EM.Terrano assumes that your transmitter is a vertically polarized (Z-directed) resonant half-wave dipole antenna. This antenna has an almost omni-directional radiation pattern in all azimuth directions. It also has radiation nulls along the axis of the dipole. You can change the direction of the dipole and orient it along the X or Y axes using the provided drop-down list. The second choice of two orthogonally polarized isotropic radiators is an abstract source that is used for Your SBR Simulation ==polarimetric channel characterization as will be discussed later.
Like every You can override the default radiator option and select any other electromagnetic solverkind of antenna with a more complicated radiation pattern. For this purpose, you have to import a radiation pattern data file to EM.Terrano. You can model any radiating structure using [[EM.Cube]]'s SBR ray tracer requires an excitation source and one or more observables for generation of simulation dataother computational modules, [[EM. Tempo]], [[EM.Terrano offers several types of sources Picasso]], [[EM.Libera]] or [[EM.Illumina]], and observables generate a 3D radiation pattern data file for it. The far-field radiation patter data are stored in a SBR simulationspecially formatted file with a "'''. You can mix RAD'''" file extension. This file contains columns of spherical φ and match different source types and observable types depending on θ angles as well as the requirements real and imaginary parts of your modeling problemthe complex-valued far-zone electric field components '''E<sub>θ</sub>''' and '''E<sub>φ</sub>'''. The available source types are:θ- and φ-components of the far-zone electric field determine the polarization of the transmitting radiator.
* '''[[#Defining Transmitter Sets {{Note| Transmitter]]'''* '''[[#Defining_a_Hertzian_Dipole_Source | Hertzian Dipole]]'''By default, EM.Terrano assumes a vertical half-wave dipole radiator for your point transmitter set.}}
The available observables types are :A transmitter set always needs to be associated with an existing base location set with one or more point objects in the project workspace. Therefore, you cannot define a transmitter for your scene before drawing a point object under a base location set.
* '''[[#Defining Receiver Sets Image:Info_icon.png| Receiver40px]]'''* '''[[#Defining_a_Hertzian_Dipole_Source | Field Sensor]]'''* '''[[#Computing_Radiation_Patterns_In_SBR | Far Field Radiation Pattern]]'''* Click here to learn how to define a '''[[Hybrid_Modeling_using_Multiple_Simulation_EnginesGlossary_of_EM.Cube%27s_Materials,_Sources,_Devices_%26_Other_Physical_Object_Types#Generating_Huygens_Surface_Data Point_Transmitter_Set | Huygens SurfacePoint Transmitter Set]]'''.
A short dipole source is the simplest type of excitation for your propagation scene. A short dipole has an almost "omni-directional" radiation pattern, and is the closest thing to an isotropic radiator. EM.<table><tr><td> [[Image:Terrano does not provide a theoretical/hypothetical isotropic transmitter because its SBR solver is fully polarimetric and requires a real physical radiator for ray generationL1 Fig11. A png|thumb|left|480px|The point transmitter is a more sophisticated source that requires a base point as well as an imported radiation pattern file with a '''.RAD''' file extensionset definition dialog.]] </td></tr></table>
Of Once you define a new transmitter set, its name is added in the above list of EM.Terrano's observables types, receivers are ''Transmitters''' section of the ones you would typically use for your propagation scenesnavigation tree. Unlike a The color of all the base points associated with the newly defined transmitterset changes, a receiver and an additional little ball with the transmitter color (red by default does not require an imported radiation pattern file) appears at the location of each associated base point. A default receiver is assumed to be polarization-matched to You can open the incoming rayproperty dialog of the transmitter set and modify a number of parameters including the '''Source Power''' in Watts and the broadcast signal '''Phase''' in degrees. The other three observable typesdefault transmitter power level is 1W or 30dBm. There is also a check box labeled '''Use Custom Input Power''', field sensorwhich is checked by default. In that case, far fields the power and Huygens surface phase boxes are primarily used in applications that utilize enabled and you can change the default 1W power and 0° phase values as you wish. [[EM.Terrano as an asymptotic electromagnetic field solverCube]]'s ". The Huygens surface observable RAD" radiation pattern files usually contain the value of "Total Radiated Power" in their file header. This quantity is primarily calculated based on the particular excitation mechanism that was used for to generate the pattern file in the original [[Hybrid Modeling using Multiple Simulation Engines|hybrid modeling using multiple simulation enginesEM.Cube]]module. When the "Use Custom Input Power" check box is unchecked, EM.Terrano will use the total radiated power value of the radiation file for the SBR simulation.
{{Note| In order to define either transmitters or receiversmodify any of the transmitter set's parameters, first you have need to define base points. For a transmitterselect the "User Defined Antenna" option, even if you additionally need want to import a radiation pattern file from one of [[EM.Cube]]'s other computational moduleskeep the vertical half-wave dipole as your radiator.}}
== Defining Transmitters & Receivers for Your Propagation Scene ==<table><tr><td> [[File:NewTxProp.png|thumb|left|720px|The property dialog of a point transmitter set.]]</td></tr></table>
=== Defining Your transmitter in EM.Teranno is indeed more sophisticated than a simple radiator. It consists of a basic "Transmitter Sets ===Chain" that contains a voltage source with a series source resistance, and connected via a segment of transmission line to a transmit antenna, which is used to launch the broadcast signal into the free space. The transmitter's property dialog allows you to define the basic transmitter chain. Click the {{key|Transmitter Chain}} button of the Transmitter Set dialog to open the transmitter chain dialog. As shown in the figure below, you can specify the characteristics of the baseband/IF amplifier, mixer and power amplifier (PA) including stage gains and impedance mismatch factors (IMF) as well as the characteristics of the transmission line segment that connects the PA to the antenna. Note that the transmit antenna characteristics are automatically filled using the contents of the imported radiation pattern data file. The transmitter Chain dialog also calculates and reports the "Total Transmitter Chain Gain" based on your input. When you close this dialog and return to the Transmitter Set dialog, you will see the calculated value of the Effective Isotropic Radiated Power (EIRP) of your transmitter in dBm.
A {{Note| If you do not modify the default parameters of the transmitter chain, a 50-Ω conjugate match condition is a point radiator with a fully defined polarimetric radiation pattern over assumed and the entire 3D space in power delivered to the spherical coordinate systemantenna will be -3dB lower than your specified baseband power. You can model a radiating structure using }} <table><tr><td> [[EMFile:NewTxChain.Tempopng|thumb|left|720px|EM.TEmpo]], [[EMTerrano's point transmitter chain dialog.Picasso]], [[EM.Libera]] or [[EM.Illumina]] and generate a 3D radiation pattern data file for it. These data are stored in a specially formatted file with a "'''.RAD'''" file extension. It contains columns of spherical φ and θ angles as well as the real and imaginary parts of the complex-valued far field components '''E<sub/td>θ</subtr>''' and '''E<sub>φ</subtable>'''. The θ- and φ-components of the far-zone electric field determine the polarization of the transmitting radiator.
[[Image:Info_icon.png|40px]] Click here to learn more about === Defining a Point Receiver Set in the format of '''[[Data_Visualization_and_Processing#Far_Field_Data_Files | Radiation Pattern Files]]'''.Formal Way ===
To define a transmitter source Receivers act as observables in EMa propagation scene.Terrano, first you The objective of a SBR simulation is to calculate the far-zone electric fields and the total received power at the location of a receiver. You need to have define at least one '''Base Point''' receiver in your project workspacethe scene before you can run a SBR simulation. Follow Similar to a transmitter, a receiver is a point radiator, too. EM.Terrano gives you three options for the procedure belowradiator associated with a point receiver set:
* RightHalf-click on the '''Transmitters''' item of the navigation tree and select '''Insert New Transmitter Set...''' from the contextual menu. This opens of the Transmitter Set dialog.wave dipole* Choose a name and color for your transmitter set. Polarization matched isotropic radiator* From the dropdown list labeled '''Associated Base Point Set''', select the desired set.* In the "Custom Pattern [[Parameters]]", click the {{key|Import Pattern}} button to set the path for the radiation data file. This opens up the standard [[Windows]] Open dialog, with the default file type or extension set to '''.RAD'''. Browse your folders to find the right data file. * You can also rotate the imported User defined antenna pattern about the three principal axes. Enter the rotation angles other than the zero default values, if necessary.* Click the {{key|OK}} button of the dialog to close it.
A new transmitter set entry is added in the '''Transmitters''' section of the navigation tree. After defining a transmitter setBy default, the base points associated with it change their color to the transmitter color, which is red by defaultEM. In the Transmitter Set dialog, you can also set the '''Baseband Power''' of Terrano assumes that your transmitter in Watts and its '''Phase''' in degrees. There receiver is a check box labeled '''Custom Power''', which is checked by defaultvertically polarized (Z-directed) resonant half-wave dipole antenna. In that case, the power and phase boxes are enabled and you You can change the default 1W power direction of the dipole and 0° phase values as you wishorient it along the X or Y axes using the provided drop-down list. [[EM.Cube]]'s ".RAD" An isotropic radiator has a perfect omni-directional radiation pattern files usually contain the value of "Total Radiated Power" in their file headerall azimuth and elevation directions. This quantity is calculated based on An isotropic radiator doesn't exist physically in the particular excitation mechanism that was real world, but it can be used simply as a point in space to generate compute the pattern file in the original [[EM.Cube]] module. When the "Custom Power" check box is unchecked, EM.Terrano will use the total radiated power value of the radiation file for SBR calculationselectric field.
EMYou may also define a complicated radiation pattern for your receiver set.Terrano allows In that case, you need to define import a basic '''Heterodyne Transmitter Chain'''radiation pattern data file to EM. Click Terrano similar to the case of a transmitter set.  {{keyNote|Transmitter ChainBy default, EM.Terrano assumes a vertical half-wave dipole radiator for your point receiver set.}} button of the Transmitter Set dialog  Similar to open the Transmitter Chain dialog. As shown in the figure belowtransmitter sets, you can specify define a receiver set by associating it with an existing base location set with one or more point objects in the characteristics of project workspace. All the baseband/IF amplifier, mixer and power amplifier (PA) including stage gains and impedance mismatch factors (IMF) as well as the characteristics of the transmission line segment that connects the PA receivers belonging to the antenna. Note that same receiver set have the transmitting antenna characteristics are automatically filled from using contents same radiator type. A typical propagation scene contains one or few transmitters but usually a large number of the radiation filereceivers. The transmitter Chain dialog also calculates and reports the "Total Transmitter Chain Gain" based on your input. When you close this dialog and return to the Transmitter Set dialogTo generate a wireless coverage map, you will see the calculated value of the Effective Isotropic Radiated Power (EIRP) need to define an array of points as your transmitter in dBmbase location set.  [[Image:Info_icon.png|40px]] Click here to learn how to define a '''[[Glossary_of_EM.Cube%27s_Simulation_Observables_%26_Graph_Types#Point_Receiver_Set | Point Receiver Set]]'''.
{{Note| If you do not modify the default [[parameters]] of the transmitter chain, a 50-Ω conjugate match condition is assumed and the power delivered to the antenna will be -3dB lower than your specified baseband power.}}
<table>
<tr>
<td> [[FileImage:PROP20(1)Terrano L1 Fig12.png|thumb|400pxleft|EM.Terrano's Transmitter dialog with a user defined pattern selected.]] </td><td> [[File:PROP20A.png480px|thumb|600px|EM.Terrano's Transmitter Chain The point receiver set definition dialog.]] </td>
</tr>
</table>
=== Defining Receiver Sets ===Once you define a new receiver set, its name is added to the '''Receivers''' section of the navigation tree. The color of all the base points associated with the newly defined receiver set changes, and an additional little ball with the receiver color (yellow by default) appears at the location of each associated base point. You can open the property dialog of the receiver set and modify a number of parameters.
<table><tr><td> [[File:PROP21(1)NewRxProp.png|thumb|400pxleft|EM.Terrano's preliminary Receiver 720px|The property dialog.]] Receivers act as observables in a propagation scene. The objective of a SBR simulation is to calculate the far-zone electric fields and the total received power at the location of a point receiver. In that sense, receivers indeed act as field observation points. You need to define at least one receiver in the scene before you can run a SBR simulation. You define the receivers of your scene by associating them with the base sets you have already defined in the project workspace. Unlike transmitters that usually one or few, a typical propagation scene may involve a large number of receivers. To generate a wireless coverage map, you need to define an array of points as your base set. ]]</td></tr></table>
To define In the Receiver Set dialog, there is a drop-down list labeled '''Selected Element''', which contains a list of all the individual receivers belonging to the receiver observable in EMset.TerranoAt the end of an SBR simulation, follow the procedure below:button labeled {{key|Show Ray Data}} becomes enabled. Clicking this button opens the Ray Data dialog, where you can see a list of all the received rays at the selected receiver and their computed characteristics.
* RightIf you choose the "user defined antenna" option for your receiver set, it indeed consists of a basic "Receiver Chain" that contains a receive antenna connected via a segment of transmission line to the low-click on noise amplifier (LNA) that is terminated in a matched load. The receiver set's property dialog allows you to define the basic receiver chain. Click the {{key|Receiver Chain}} button of the Receiver Set dialog to open the receiver chain dialog. As shown in the figure below, you can specify the characteristics of the LNA such as its gain and noise figure in dB as well as the characteristics of the transmission line segment that connects the antenna to the LNA. Note that the receiving antenna characteristics are automatically filled from using contents of the radiation file. You have to enter values for antenna's ''Receivers'Brightness Temperature'' item ' as well as the temperature of the navigation tree transmission line and select the receiver's ambient temperature. The effective '''Insert New Receiver Set...Bandwidth''' from is assumed to be 100MHz, which you can change for the contextual menu. This opens purpose of the preliminary Receiver Set dialognoise calculations.* Choose a name The Receive Chain dialog calculates and for reports the "Noise Power" and "Total Receiver Chain Gain" based on your receiver setinput. * From At the dropdown list labeled '''Associated Base point Set'''end of an SBR simulation, select the desired receiver power and signal-noise ratio (SNR) of the selected receiver are calculated and they are reported in the receiver setdialog in dBm and dB, respectively.* Click You can examine the {{key|OK}} button properties of all the dialog to close itindividual receivers and all the individual rays received by each receiver in your receiver set using the "Selected Element" drop-down list.
A new receiver set entry is added in the '''Receivers''' section of the navigation tree<table><tr><td> [[File:NewRxChain. After defining a receiver set, the base points associated with it change their color to the receiver color, which is yellow by defaultpng|thumb|left|720px|EM. The first element of the set is represented by a larger ball of the same color indicating that it is the selected Terrano's point receiver in the scenechain dialog. ]] </td></tr></table>
The Receiver Set Dialog is also used to access individual receivers of the set for data visualization at the end of a simulation. At the end of an SBR simulation, the button labeled "Show Ray Data" becomes enabled. Clicking this button opens the Ray Data Dialog, where you can see a list of all the received rays at the selected receiver === Modulation Waveform and their computed characteristics. Detection ===
{{Note| EM.Terrano receivers, by default, are defined as isotropic or polarization-matched radiatorsallows you to define a digital modulation scheme for your communication link.}}There are currently 17 waveforms to choose from in the receiver set property dialog:
If you want directional radiators for your receiver set, you need to open the Receiver dialog by right*OOK*M-clicking on the receiver set's name in the navigation tree and opening its property dialog from the contextual menu. In the "Radiator Properties" section of this dialog, select the '''User Defined''' radio button. Similar to the case of transmitter set, you can import a '''.RAD''' radiation pattern file using the {{key|Import Pattern}} button. You can also rotate the imported radiation pattern by setting '''Rotation Angles''' different than the default zero values. ary ASK *Coherent BFSKEM.Terrano allows you to define a basic '''Heterodyne Receiver Chain'''. Click the {{key|Receiver Chain}} button of the Receiver Set dialog to open the Receiver Chain dialog. As shown in the figure below, you can specify the characteristics of the Low*Coherent QFSK*Coherent M-Noise Amplifier (LNA), mixer and basebandary FSK*Non-Coherent BFSK*Non-Coherent QFSK*Non-Coherent M-ary FSK*BPSK*QPSK*Offset QPSK*M-ary PSK*DBPSK*pi/IF amplifier including stage gains and impedance mismatch factors 4 Gray-Coded DQPSK*M-ary QAM*MSK*GMSK (IMF) as well as the characteristics of the transmission line segment that connects the antenna to the LNA. Note that the receiving antenna characteristics are automatically filled from using contents of the radiation file. You have to enter values for antenna's '''Brightness Temperature''' as well as the temperature of the transmission line and the receiver's ambient temperature. The effective '''Receiver Bandwidth''' is assumed to be 100MHz, which you can change for the purpose of noise calculations. You also need to enter values for the '''Noise Figure''' of various active devices in the receiver chain. The Receive Chain dialog calculates and reports the "Noise Power" and "Total Receiver Chain Gain" based on your inputBT = 0. 3)
In the Receiver Set dialogabove list, there you need to specify the '''No. Levels (M)''' for the Mary modulation schemes, from which the '''No. Bits per Symbol''' is determined. You can also define a dropdown list labeled "Selected Receiver"bandwidth for the signal, which contains has a list default value of all the individual receivers belonging to the receiver set100MHz. At Once the end SNR of an SBR simulationthe signal is found, given the receiver power specified modulation scheme, the E<sub>b</sub>/N<sub>0</sub> parameter is determined, from which the bit error rate (BER) is calculated. The Shannon â Hartley Equation estimates the channel capacity: <math> C = B \log_2 \left( 1 + \frac{S}{N} \right) </math> where B in the bandwidth in Hz, and signal-noise ratio C is the channel capacity (SNRmaximum data rate) expressed in bits/s. The spectral efficiency of the selected receiver are channel is defined as <math> \eta = \log_2 \left( 1 + \frac{S}{N} \right) </math> The quantity E<sub>b</sub>/N<sub>0</sub> is the ratio of energy per bit to noise power spectral density. It is a measure of SNR per bit and is calculated from the following equation: <math> \frac{E_b}{N_0} = \frac{ 2^\eta - 1}{\eta} </math> where η is the spectral efficiency.  The relationship between the bit error rate and reported in dBm E<sub>b</sub>/N<sub>0</sub> depends on the modulation scheme and dBdetection type (coherent vs. non-coherent). For example, respectivelyfor coherent QPSK modulation, one can write: <math> P_b = 0. The 5 \; \text{erfc} \left( \sqrt{key|Show Ray Data\frac{E_b}{N_0} button also allows you } \right) </math> where P<sub>b</sub> is the bit error rate and erfc(x) is the complementary error function: <math> \text{erfc}(x) = 1-\text{erf}(x) = \frac{2}{\sqrt{\pi}} \int_{x}^{\infty} e^{-t^2} dt </math> The '''Minimum Required SNR''' parameter is used to see determine link connectivity between each transmitter and receiver pair. If you check the details box labeled '''Generate Connectivity Map''' in the receiver set property dialog, a binary map of all the received rays propagation scene is generated by EM.Terrano, in which one color represents a closed link and another represent no connection depending on the selected color map type of the graph. EM.Terrano also calculates the '''Max Permissible BER''' corresponding to the specified minimum required SNR and displays it in the receiverset property dialog.  === A Note on EM.Terrano's Native Dipole Radiators === When you define a new transmitter set or a new receiver set, EM.Terrano assigns a vertically polarized half-wave dipole radiator to the set by default. The radiation pattern of this native dipole radiators is calculated using well-know expressions that are derived based on certain assumptions and approximations. For example, the far-zone electric field of a vertically-polarized dipole antenna can be expressed as:  <math> E_\theta(\theta,\phi) \approx j\eta_0 I_0 \frac{e^{-jk_0 r}}{2\pi r} \left[ \frac{\text{cos} \left( \frac{k_0 L}{2} \text{cos} \theta \right) - \text{cos} \left( \frac{k_0 L}{2} \right) }{\text{sin}\theta} \right] </math> <math> E_\phi(\theta,\phi) \approx 0 </math> where k<sub>0</sub> = 2π/λ<sub>0</sub> is the free-space wavenumber, λ<sub>0</sub> is the free-space wavelength, η<sub>0</sub> = 120π Ω is the free-space intrinsic impedance, I<sub>0</sub> is the current on the dipole, and L is the length of the dipole. The directivity of the dipole antenna is given be the expression: <math> D_0 \approx \frac{2}{F_1(k_0L) + F_2(k_0L) + F_3(k_0L)} \left[ \frac{\text{cos} \left( \frac{k_0 L}{2} \text{cos} \theta \right) - \text{cos} \left( \frac{k_0 L}{2} \right) }{\text{sin}\theta} \right]^2 </math> with  <math> F_1(x) = \gamma + \text{ln}(x) - C_i(x) </math> <math> F_2(x) = \frac{1}{2} \text{sin}(x) \left[ S_i(2x) - 2S_i(x) \right] </math> <math> F_3(x) = \frac{1}{2} \text{cos}(x) \left[ \gamma + \text{ln}(x/2) + C_i(2x) - 2C_i(x) \right] </math>  where γ = 0.5772 is the Euler-Mascheroni constant, and C<sub>i</sub>(x) and S<sub>i</sub>(x) are the cosine and sine integrals, respectively:  <math> C_i(x) = - \int_{x}^{\infty} \frac{ \text{cos} \tau}{\tau} d\tau </math> <math> S_i(x) = \int_{0}^{x} \frac{ \text{sin} \tau}{\tau} d\tau </math>  In the case of a half-wave dipole, L = λ<sub>0</sub>/2, and D<sub>0</sub> = 1.643. Moreover, the input impedance of the dipole antenna is Z<sub>A</sub> = 73 + j42.5 Ω. These dipole radiators are connected via 50Ω transmission lines to a 50Ω source or load. Therefore, there is always a certain level of impedance mismatch that violates the conjugate match condition for maximum power.
<table>
<tr>
<td> [[File:PROP22Dipole radiators.png|thumb|400px720px|EM.Terrano's Receiver dialog with an isotropic radiator selected.]] </td><td> [[File:PROP22A.png|thumb|600px|EM.Terrano's Receiver Chain dialognative half-wave dipole transmitter and receiver.]] </td>
</tr>
</table>
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On the other hand, we you specify a user-defined antenna pattern for the transmitter or receiver sets, you import a 3D radiation pattern file that contains all the values of E<sub>θ</sub> and E<sub>φ</sub> for all the combinations of (θ, φ) angles. Besides the three native dipole radiators, [[EM.Cube]] also provides 3D radiation pattern files for three X-, Y- and Z-polarized half-wave resonant dipole antennas. These pattern data were generated using a full-wave solver like [[EM.Libera]]'s wire MOM solver. The names of the radiation pattern files are:
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* DPL_STD_X.RAD
* DPL_STD_Y.RAD
* DPL_STD_Z.RAD
Â
and they are located in the folder "\Documents\EMAG\Models" on your computer. Note that these are full-wave simulation data and do not involve any approximate assumptions. To use these files as an alternative to the native dipole radiators, you need to select the '''User Defined Antenna Pattern''' radio button as the the radiator type in the transmitter or receiver set property dialog.
=== A Note on the Rotation of Antenna Radiation Patterns ===
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<td> [[File:PROP22B.png|thumb|200px300px|The local coordinate system of a linear dipole antenna.]] </td><td> [[File:PROP22C.png|thumb|370px600px|Rotating the dipole antenna by +90° about the local Y-axis.]] </td></tr></table><table><tr><td> [[File:PROP22D.png|thumb|480px720px|Rotating the dipole antenna by +90° about the local X-axis and then by -45° by the local Y-axis.]] </td>
</tr>
</table>
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<td> [[Image:prop_txrx1_tnPROP MAN8.png|thumb|400pxleft|Transmitter 640px|A transmitter (red) and a grid of receivers (yellow) adjusted above an uneven a plateau terrain surface.]] </td><td> [[Image:prop_txrx2_tn.png|thumb|400px|The underlying base point sets (blue and orange dots) associated with the adjusted transmitters and receivers on the terrainare also visible in the figure.]] </td>
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== Using Discretizing the Propagation Scene in EM.Terrano as an Asymptotic Field Solver ==
[[File:PROP18(1).png|thumb|350px|EM.Terrano's Short Dipole Source dialog.]]The simplest SBR simulation can be performed using a short dipole source with a specified field sensor plane. As an asymptotic EM solver, EM.Terrano then computes the electric and magnetic fields radiated by your dipole source in the presence of your multipath propagation environment. EM.Terrano's short dipole source and field sensor observable are very similar === Why Do You Need to those of [[EM.Cube]]'s other computational modules. You can also compute Discretize the far field radiation patterns of a dipole in the presence of surrounding scatterers or compute the Huygens surface data for use in [[EM.Cube]]'s other modules.<!--[[Image:Info_icon.png|40px]] Click here to learn more about using EM.Terrano as an '''[[Asymptotic Field Solver]]'''.-->Scene? ===
=== Defining EM.Terrano's SBR solver uses a Hertzian Dipole Source ===method known as Geometrical Optics (GO) in conjunction with the Uniform Theory of Diffraction (UTD) to trace the rays from their originating point at the source to the individual receiver locations. Rays may hit obstructing objects on their way and get reflected, diffracted or transmitted. EM.Terrano's SBR solver can only handle diffraction off linear edges and reflection from and transmission through planar interfaces. When an incident ray hits the surface of the obstructing object, a local planar surface assumption is made at the specular point. The assumptions of linear edges and planar facets obviously work in the case of a scene with cubic buildings and a flat global ground.
A short dipole is In many practical scenarios, however, your buildings may have curved surfaces, or the simplest way of exciting a structure in [[terrain may be irregular. EM.Terrano]]. It is also the closest thing allows you to an omnidirectional radiatordraw any type of surface or solid geometric objects such as cylinders, cones, etc. The direction under impenetrable and penetrable surface groups or orientation of the short dipole determines its polarizationpenetrable volumes. Note that EM.Terrano does not offer an isotropic radiator as 's mesh generator creates a source type because it triangular surface mesh of all the objects in your propagation scene, which is called a polarimetric ray tracerfacet mesh. A short dipole source acts like an infinitesimally small ideal current sourceEven the walls of cubic buildings are meshed using triangular cells. A short dipole source appears as a small arrow in your sceneThis enables EM. The total radiated power by your dipole source is calculated and displayed in Watts in its property dialogTerrano to properly discretize composite buildings made of conjoined cubic objects.
Unlike [[Image:Info_iconEM.png|40pxCube]] Click here to learn more about ''s other computational modules, the density or resolution of EM.Terrano'[[Common_Excitation_Source_Types_in_EMs surface mesh does not depend on the operating frequency and is not expressed in terms of the wavelength.Cube#Hertzian_Dipole_Sources | Hertzian Dipole Sources]]''The sole purpose of EM.Terrano's facet mesh is to discretize curved and irregular scatterers into flat facets and linear edges. Therefore, geometrical fidelity is the only criterion for the quality of a facet mesh. It is important to note that discretizing smooth objects using a triangular surface mesh typically creates a large number of small edges among the facets that are simply mesh artifacts and should not be considered as diffracting edges. For example, each rectangular face of a cubic building is subdivided into four triangles along the two diagonals. The four internal edges lying inside the face are obviously not diffracting edges. A lot of subtleties like these must be taken into account by the SBR solver to run accurate and computationally efficient simulations.
=== Defining a Field Sensor Generating the Facet Mesh ===
[[File:PROP18(2).png|thumb|350px|EM.TerranoYou can view and examine the discretized version of your scene's Field Sensor dialog]]As an asymptotic electromagnetic field solver, objects as they are sent to the SBR simulation engine . You can compute adjust the electric mesh resolution and magnetic field distributions in a specified plane. In order to view these field distributions, you must first define field sensor observables before running increase the SBR simulation. To do that, right click on the '''Field Sensors''' item in the '''Observables''' section geometric fidelity of the navigation tree discretization by creating more and select '''Insert New Observablefiner triangular facets...'''. The Field Sensor Dialog opens up. At On the top of the dialog and in the section titled '''Sensor Plane Location'''other hand, first you need may want to set reduce the plane of field calculation. In the dropdown box labeled '''Direction''', you have three options X, Y, mesh complexity and Z, representing send to the"normals" SBR engine only a few coarse facets to the XY, YZ and ZX planes, respectivelymodel your buildings. The default direction resolution of EM.Terrano's facet mesh generator is Z, i.e. XY plane parallel to the substrate layers. In controlled by the three boxes labeled '''CoordinatesCell Edge Length'''parameter, you set the coordinates of the center of the plane. Then, you specify the '''Size''' of the plane which is expressed in project length units, and finally set the '''Number of Samples''' along the two sides of the sensor plane. The larger the number default mesh cell size of samples, the smoother the near field map will appear100 units might be too large for non-flat objects. You may have to set a smaller cell edge length in EM.  Once you close the Field Sensor Terrano's Mesh Settings dialog, its name is added under the '''Field Sensors''' node of the Navigation Tree. At the end of along with a SBR simulation, lower curvature angle tolerance value to capture the field sensor nodes in the Navigation Tree become populated by the magnitude and phase plots curvature of the three vectorial components of the electric ('''E''') and magnetic ('''H''') field as well as the total electric and magnetic fields. [[Image:Info_icon.png|40px]] Click here to learn more about '''[[Data_Visualization_and_Processing#Visualizing_3D_Near-Field_Maps | Visualizing 3D Near Field Maps]]'''your curved structures adequately.
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<td> [[Image:PROP18Mprop_manual-29.png|thumb|450pxleft|Computed total electric field distribution of a vertical short dipole radiator 2m above the default global ground at 1GHz480px|EM.Terrano's mesh settings dialog.]] </td><td> [[Image:PROP18N.png|thumb|450px|Computed total magnetic field distribution of a vertical short dipole radiator 2m above the default global ground at 1GHz.]] </td>
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=== Computing Radiation Patterns In SBR ===[[Image:Info_icon.png|30px]] Click here to learn more about '''[[Preparing_Physical_Structures_for_Electromagnetic_Simulation#Working_with_EM.Cube.27s_Mesh_Generators | Working with Mesh Generator]]'''.
[[File:PROP18(3).png|thumb|350px|EM.Terrano's Radiation Pattern dialog.]][[EM.Terrano]] lets you compute the effective far-field radiation pattern of your radiating structure in the presence of surrounding scatterers and obstructing objects. Computing the radiation pattern of an antenna or any radiating structure in [[EM.Cube]]'s full-wave computational modules like [[EM.Tempo]], [[EM.Picasso]] or [[EM.Libera]] is fairly straightforward. Using [[EM.Illumina]] you can use an asymptotic physical optics solver to model the effects of the mounting platform on the performance of an installed antenna. Computing radiation patterns in [[EM.Terrano]] may not seem intuitive at first because you have to import the radiation patterns from external data files after all. In order to visualize a radiation pattern in [[EM.Terrano]], you have to define a "Far Fields" observable. To do so, right-click on the '''Far Fields''' item in the '''Observables''' section of the navigation tree and select '''Insert New Radiation Pattern...''' from the contextual menu. This opens up the Radiation Pattern dialog. You can accept most of the default settings. The most important [[parameters]] to change are the angular resolutions. These are called '''Theta Angle Increment''' and '''Phi Angle Increment''', both of which have default values of 5°. When you define a far-field observable in [[EM.Terrano]], a collection of <u>invisible</u>, isotropic receivers are placed on the surface of a large sphere that encircles your propagation scene and all of its objects. These receivers are equally spaced on the spherical surface at a spacing that is determined by your specified angular resolutions. In most cases, you need to define angular resolutions of at least 1° or smaller. Note that this is different than the transmitter rays' angular resolution. You may have a large number of transmitted rays but not enough receivers to compute the effective radiation pattern at all 3D angles. Also keep in mind that with 1° Theta and Phi angle increments, you will have a total of 181 × 361 = 65,341 spherically placed receivers in your scene.  {{Note| Computing radiation patterns using [[EM.Terrano]]'s SBR solver typically takes much longer computation times than using [[EM.Cube]]'s other computational modules.}} [[Image:Info_icon.png|40px30px]] Click here to learn more about the properties of '''[[Data_Visualization_and_ProcessingGlossary_of_EM.Cube%27s_Simulation-Related_Operations#Visualizing_3D_Radiation_Patterns Facet_Mesh | Visualizing 3D Radiation Patterns]]'''EM. [[Image:Info_icon.png|40px]] Click here to learn more about Terrano'''[[Data_Visualization_and_Processing#2D_Radiation_and_RCS_Graphs | Plotting 2D Radiation Graphss Facet Mesh Generator]]'''.
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<td> [[Image:PROP18PUrbanCanyon2.png|thumb|450pxleft|Computed 3D radiation pattern 640px|The facet mesh of two vertical short dipole radiators placed 1m apart the buildings in the free space at 1GHzurban propagation scene generated by EM.Terrano's Random City wizard with a cell edge length of 100m.]] </td></tr><tr><td> [[Image:UrbanCanyon3.png|thumb|left|640px|The facet mesh of the buildings in the urban propagation scene generated by EM.Terrano's Random City wizard with a cell edge length of 10m.]] </td>
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== Discretizing the Propagation Scene Running Ray Tracing Simulations in EM.Terrano ==
=== Why Do You Need to Discretize the Scene? ===EM.Terrano provides a number of different simulation or solver types:
EM.Terrano's * 3D Field Solver* SBR ray tracer uses a method known as Geometrical Optics (GO) in conjunction with the Uniform Theory of Diffraction (UTD) to traces the rays from their originating point at the source to the individual receiver locations. Ray may hit obstructing objects on their way and get reflected, diffracted or transmitted. EM.Terrano's SBR solver can only handle diffraction off linear edges and reflection from and transmission through planar material interfaces. The underlying theory for calculation of reflection, transmission and diffraction coefficients indeed assumes material media of infinite extents. When a ray hits a specular point on the surface of the obstructing object, a local planar surface assumption is made at the specular point. Channel Analyzer* Log-Haul Channel Analyzer* Communication Link Solver* Radar Link Solver
[[Image:Info_iconThe first three simulation types are described below.png|40px]] Click here to learn more about the theory For a description of EM.Terrano'''[[SBR Method]]'''s Radar Simulator, follow this link.
If your propagation scene contains only cubic buildings on the flat global ground, the assumptions of linear edges and planar facets hold well although they violate the infinite extents assumption. In many practical scenarios, however, your buildings may have curved surface or the terrain may be irregular. EM.Terrano allows you to draw any type of surface or solid CAD objects under impenetrable and penetrable surface groups or penetrable volumes. Some of these objects contain curved surfaces or curved boundaries and edges such as cylinders, cones, etc. In order to address all such cases in the most general context, EM.Terrano always uses === Running a triangular surface mesh of all the objects in your propagation scene. Even rectangular facets of cubic buildings are meshed using triangular cells. This is done to be able to properly discretize composite buildings made of conjoined cubic objects. Single-Frequency SBR Analysis ===
=== Generating Its main solver is the '''3D SBR Mesh ===Ray Tracer'''. Once you have set up your propagation scene in EM.Terrano and have defined sources/transmitters and observables/receivers for your scene, you are ready to run a SBR ray tracing simulation. You set the simulation mode in EM.Terrano's simulation run dialog. A single-frequency SBR analysis is a single-run simulation and the simplest type of ray tracing simulation in EM.Terrano. It involves the following steps:
[[Image:prop_manual-29* Set the units of your project and the frequency of operation.png|thumb|350px|EM.TerranoNote that the default project unit is 's Mesh Settings dialog.]] Unlike [[EM.Cube]]'s other computational modules'millimeter'''. Wireless propagation problems usually require meter, the density mile or resolution of EMkilometer as the project unit.Terrano's surface mesh does not depend on * Create the operating frequency blocks and is not expressed in terms of draw the wavelengthbuildings at the desired locations. Its sole purpose is to discretize curved * Keep the default ray domain and irregular scatterers into flat facets and linear edges. Therefore, geometrical fidelity is accept the only criterion for the quality of default global ground or change its material properties.* Define an SBR meshexcitation source and observables for your project. It is important * If you intend to note that discretizing smooth objects using a triangular surface mesh typically creates a large number of small edges among the facets that are simply mesh artifacts use transmitters and should not be considered as diffracting edges. For examplereceivers in your scene, each rectangular face of a cubic building is subdivided into four triangles along first define the two diagonals. The four internal edges lying inside required base sets and then define the face are obviously not diffracting edgestransmitter and receiver sets based on them. A lot of subtleties like these must be taken into account by * Run the SBR solver to run accurate simulation engine.* Visualize the coverage map and computationally efficient simulationsplot other data.
You can view and examine the discretized version of your scene objects as they are sent to the SBR simulation engineaccess EM. You can adjust the mesh resolution and increase the geometric fidelity of discretization Terrano's Simulation Run dialog by creating more and finer triangular facets. On clicking the other hand, you may want to reduce the mesh complexity and send to the SBR engine only a few coarse facets to model your buildings. Unlike '''Run''' [[EMFile:run_icon.Cubepng]]'s other computational modules that express the default mesh density based on the wavelength, the resolution button of the SBR mesh generator is controlled by the '''Mesh Cell SizeSimulate Toolbar''' parameter, which is expressed in project length unitsor by selecting '''Simulate → Run. The default mesh cell size of 100 units might be too large for non-flat objects. You may have to set a smaller mesh cell size in EM.Terrano's Mesh Settings dialog'' or using the keyboard shortcut {{key|Ctrl+R}}. When you click the {{key|Run}} button, along with a lower curvature angle tolerance value to capture new window opens up that reports the curvature different stages of your curved structures adequatelythe SBR simulation and indicates the progress of each stage. After the SBR simulation is successfully completed, a message pops up and prompts the completion of the process.
<table><tr><td> [[Image:Info_iconTerrano L1 Fig16.png|40px]] Click here to learn more about thumb|left|480px|EM.Terrano'''[[Mesh_Generation_Schemes_in_EMs simulation run dialog.Cube#Working_with_Mesh_Generator | Working with Mesh Generator ]]'''.</td></tr></table>
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<td> [[Image:PROP15BPROP MAN10.png|thumb|left|550px|The brick buildings in an urban propagation sceneEM.Terrano's output message window.]] </td><td> [[Image:PROP15C.png|thumb|550px|The triangular surface mesh of the building in the urban propagation scene.]] </td>
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== Running an = Changing the SBR Simulation Engine Settings ===
=== There are a number of SBR simulation settings that can be accessed and changed from the Ray Tracing Engine Settings Dialog. To open this dialog, click the button labeled {{key|Settings}} on the right side of the '''Select Simulation Types ===or Solver Type''' drop-down list in the Run Dialog. EM.Terrano's SBR simulation engine allows you to separate the physical effects that are calculated during a ray tracing process. You can selectively enable or disable '''Reflection/Transmission''' and '''Edge Diffraction''' in the "Ray-Block Interactions" section of this dialog. By default, ray reflection and transmission and edge diffraction effects are enabled. Separating these effects sometimes help you better analyze your propagation scene and understand the impact of various blocks in the scene.
[[Image:PROP12.png|thumb|400px|EM.Terranoallows a finite number of ray bounces for each original ray emanating from a transmitter. This is very important in situations that may involve resonance effects where rays get trapped among multiple surfaces and may bounce back and forth indefinitely. This is set using the box labeled "'''s Simulation Run dialogMax No.]]EMRay Bounces'''", which has a default value of 10.Terrano offers three types Note that the maximum number of ray tracing simulationsbounces directly affects the computation time as well as the size of output simulation data files. This can become critical for indoor propagation scenes, where most of the rays undergo a large number of reflections. Two other parameters control the diffraction computations:'''Max Wedge Angle''' in degrees and '''Min Edge Length''' in project units. The maximum wedge angle is the angle between two conjoined facets that is considered to make them almost flat or coplanar with no diffraction effect. The default value of the maximum wedge angle is 170°. The minimum edge length is size of the common edge between two conjoined facets that is considered as a mesh artifact and not a real diffracting edge. The default value of the minimum edge length is one project units.
* Single-Frequency Analysis<table>* Frequency Sweep<tr>* Parametric Sweep<td> [[Image:PROP MAN11.png|thumb|left|720px|EM.Terrano's SBR simulation engine settings dialog.]] </td></tr></table>
A single-frequency SBR analysis As rays travel in the scene and bounce from surfaces, they lose their power, and their amplitudes gradually diminish. From a practical point of view, only rays that have power levels above the receiver sensitivity can be effectively received. Therefore, all the rays whose power levels fall below a specified power threshold are discarded. The '''Ray Power Threshold''' is specified in dBm and has a default value of -150dBm. Keep in mind that the simplest type value of ray tracing this threshold directly affects the accuracy of the simulation and involves results as well as the size of the following steps:output data file.
* Set You can also set the unit of project scene and the frequency of operation. Note that the default project unit is '''millimeterRay Angular Resolution'''of the transmitter rays in degrees. Wireless propagation problems usually require meterBy default, mile or kilometer as every transmitter emanates equi-angular ray tubes at a resolution of 1 degree. Lower angular resolutions larger than 1° speed up the project unitSBR simulation significantly, but they may compromise the accuracy.* Create Higher angular resolutions less than 1° increase the blocks and draw accuracy of the buildings at simulating results, but they also increase the desired locationscomputation time.* Keep The SBR Engine Settings dialog also displays the default ray '''Recommended Ray Angular Resolution''' in degrees in a grayed-out box. This number is calculated based on the overall extents of your computational domain and accept as well as the default global ground or change its material propertiesSBR mesh resolution.* Define an excitation source and observables for your project.* If To see this value, you intend have to use transmitters and receivers in your scene, generate the SBR mesh first define . Keeping the required base sets and then define angular resolution of your project above this threshold value makes sure that the transmitter and receiver sets based on them.* Run small mesh facets at very large distances from the SBR simulation engine.* Visualize source would not miss any impinging ray tubes during the coverage map and plot other datasimulation.
You can access EM.Terrano's Simulation Run dialog by clicking gives a few more options for the '''Run''' [[File:run_iconray tracing solution of your propagation problem.png]] button For instance, it allows you to exclude the direct line-of -sight (LOS) rays from the '''Simulate Toolbar''' or by selecting '''Simulate > Run.final solution..''' or using There is a check box for this purpose labeled "Exclude direct (LOS) rays from the keyboard shortcut {{key|Ctrl+R}}solution", which is unchecked by default. When EM.Terrano also allows you click to superpose the {{key|Run}} button, a new window opens up received rays incoherently. In that reports case, the different stages powers of the SBR simulation and indicates the progress of each stageindividual ray are simply added to compute that total received power. After This option in the SBR simulation check box labeled "Superpose rays incoherently" is successfully completeddisabled by default, a message pops up and prompts the completion of the processtoo.
=== Changing At the SBR Engine Settings ===end of a ray tracing simulation, the electric field of each individual ray is computed and reported. By default, the actual received ray fields are reported, which are independent of the radiation pattern of the receive antennas. EM.Terrano provides a check box labeled "Normalize ray's E-field based on receiver pattern", which is unchecked by default. If this box is checked, the field of each ray is normalized so as to reflect that effect of the receiver antenna's radiation pattern. The received power of each ray is calculated from the following equation:
[[Image:PROP13.png|thumb<math> P_{ray} = \frac{ |400px|EM.Terrano's SBR Engine Settings dialog.]]There are a number of SBR simulation settings that can be accessed and changed from the SBR Settings Dialog. To open this dialog, click the button labeled \mathbf{E_{keynorm}} |Settings^2 }{2\eta_0} on the right side of the '''Select Engine''' dropdown list in the Run Dialog. EM.Terrano's SBR simulation engine allows you to separate the physical effects that are calculated during a ray tracing process. You can selectively enable or disable '''Reflection\frac{\lambda_0^2}{4\pi} </Transmission''', '''Edge Diffraction''' and '''Terrain Diffraction''' in the "Ray-Block Interactions" section of this dialog. By default, the reflection, transmission and edge diffraction effects are enabled and the terrain diffraction effects are disabled. Separating these effects sometimes help you better analyze your propagation scene and understand the impact of various blocks in the scene.math>
EM.Terrano allows a finite number of ray bounces for each original ray emanating from a transmitter. This is very important in situations It can be seen that may involve resonance effects where rays get trapped among multiple surfaces and may bounce back and forth indefinitely. This is set using if the box labeled "ray'''Max No. Ray Bounces'''"s E-field is not normalized, which has a default value of 10. Note that the maximum number of computed ray bounces directly affects the computation time as well as the size of output simulation data files. This can become critical for indoor propagation scenes, where most of the rays undergo a large number of reflections. Two other [[parameters]] control the diffraction computations: '''Max Wedge Angle''' in degrees and '''Min Edge Length''' in project units. The maximum wedge angle is the angle between two conjoined facets power will correspond to that is considered to make them almost flat or coplanar with no diffraction effect. The default value of the maximum wedge angle is 170°. The minimum edge length is size of the common edge between two conjoined facets that is considered as a mesh artifact and not a real diffracting edge. The default value of the minimum edge length is 5 project unitspolarization matched isotropic receiver.
As rays travel in the scene and bounce from surfaces, they lose their power, and their amplitudes gradually diminish. From a practical point of view, only rays that have power levels above the receiver sensitivity threshold can be effectively received. Therefore, all the rays whose power levels fall below a specified power threshold are discarded. The '''Ray Power Threshold''' is specified in dBm and has a default value of -100dBm. Keep in mind that the value of this threshold directly affects the accuracy of the simulation results as well as the size of the output data file.=== Polarimetric Channel Analysis ===
You can also set the '''Angular Resolution''' In a 3D SBR simulation, a transmitter shoots a large number of the transmitter rays in degreesall directions. By default, every transmitter emanates equi-angular ray tubes at a resolution The electric fields of 1 degree. Lower angular resolutions larger than 1° speed up these rays are polarimetric and their strength and polarization are determined by the SBR simulation significantly, but they may compromise designated radiation pattern of the accuracytransmit antenna. Higher angular resolutions less than 1° increase The rays travel in the accuracy of propagation scene and bounce from the simulating results, but ground and buildings or other scatterers or get diffracted at the building edges until they also increase reach the location of the computation timereceivers. Each individual ray has its own vectorial electric field and power. The SBR Engine Settings dialog also shows the required '''Minimum Angular Resolution''' in degrees in a greyed-out box. This number is calculated based on the overall extents electric fields of your computational domain as well as the SBR mesh resolution. To see this value, you have received rays are then superposed coherently and polarimetrically to generate compute the SBR mesh firsttotal field at the receiver locations. Keeping the angular resolution The designated radiation pattern of your project above this threshold value makes sure that the small mesh facets at very large distances from receivers is then used to compute the source would not miss any impinging ray tubes during the simulationtotal received power by each individual receiver.
=== Running an SBR Frequency Sweep ===From a theoretical point of view, the radiation patterns of the transmit and receive antennas are independent of the propagation channel characteristics. For the given locations of the point transmitters and receivers, one can assume ideal isotropic radiators at these points and compute the polarimetric transfer function matrix of the propagation channel. This matrix relates the received electric field at each receiver location to the transmitted electric field at each transmitter location. In general, the vectorial electric field of each individual ray is expressed in the local standard spherical coordinate system at the transmitter and receiver locations. In other words, the polarimetric channel matrix expresses the '''E<sub>θ</sub>''' and '''E<sub>φ</sub>''' field components associated with each ray at the receiver location to its '''E<sub>θ</sub>''' and '''E<sub>φ</sub>''' field components at the transmitter location. Each ray has a delay and θ and φ angles of departure at the transmitter location and θ and φ angles of departure at the receiver location.
[[Image:prop_run10.png|thumb|300px|To perform a polarimatric channel characterization of your propagation scene, open EM.Terrano's Frequency Settings Run Simulation dialog.]]By default, EM.Terrano performs a single-frequency analysis. You set the operational frequency of a SBR simulation in the projectand select 's ''Channel Analyzer'Frequency Dialog''from the drop-down list labeled '''Select Simulation or Solver Type'''. At the end of the simulation, which can be accessed in a number large ray database is generated with two data files called "sbr_channel_matrix.DAT" and "sbr_ray_path.DAT". The former file contains the delay, angles of ways:arrival and departure and complex-valued elements of the channel matrix for all the individual rays that leave each transmitter and arrive at each receiver. The latter file contains the geometric aspects of each ray such as hit point coordinates.
* By clicking the '''Frequency''' [[File:freq_icon.png]] button of the '''Simulate Toolbar'''.* By selecting '''Simulate > Frequency Settings...''' from the Menu Bar.* Using the keyboard shortcut {{key|Ctrl+F}}.* By double clicking the frequency section (box) of the '''Status Bar'''. === The "Near Real-Time" Polarimatrix Solver ===
You After EM.Terrano's channel analyzer generates a ray database that characterizes your propagation channel polarimetrically for all the combinations of transmitter and receiver locations, a ray tracing solution of the propagation problem can also select readily be found in almost real time by incorporating the effects of the radiation patterns of transmit and receive antennas. This is done using the '''Frequency SweepPolarimatrix Solver''' , which is the third option in of the drop-down list labeled '''Select Simulation Modeor Solver Type''' dropdown list of the ''in EM.Terrano's Run Dialog'''Simulation dialog. Click The results of the {{key|Settings}} button on Polarimatrix and 3D SBR solvers must be identical from a theoretical point of view. However, there might be small discrepancies between the right side of this dropdown list two solutions due to open up the Frequency Settings Dialogroundoff errors. In this dialog you have  Using the Polarimatrix solver can lead to set a significant reduction of the value total simulation time in sweep simulations that involve a large number of '''Start Frequency''', '''End Frequency''' transmitters and '''Number receivers. Certain simulation modes of Samples''' for you frequency sweepEM. Once you click Terrano are intended for the Polarimatrix solver only as will be described in the next section.  {{keyNote|RunIn order to use the Polarimatrix solver, you must first generate a ray database of your propagation scene using EM.Terrano's Channel Analyzer.}} button,  === EM.Terrano performs 's Simulation Modes === EM.Terrano provides a number of different simulation modes that involve single or multiple simulation runs:  {| class="wikitable"|-! scope="col"| Simulation Mode! scope="col"| Usage! scope="col"| Which Solver?! scope="col"| Frequency ! scope="col"| Restrictions|-| style="width:120px;" | [[#Running a Single-Frequency SBR Analysis | Single-Frequency Analysis]]| style="width:180px;" | Simulates the propagation scene "As Is"| style="width:150px;" | SBR, Channel Analyzer, Polarimatrix, Radar Simulator| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | None|-| style="width:120px;" | [[Parametric_Modeling_%26_Simulation_Modes_in_EM.Cube#Running_Frequency_Sweep_Simulations_in_EM.Cube | Frequency Sweep]]| style="width:180px;" | Varies the operating frequency sweep by assigning each of the ray tracer | style="width:150px;" | SBR, Channel Analyzer, Polarimatrix, Radar Simulator| style="width:120px;" | Runs at a specified set of frequency samples | style="width:300px;" | None|-| style="width:120px;" | [[Parametric_Modeling_%26_Simulation_Modes_in_EM.Cube#Running_Parametric_Sweep_Simulations_in_EM.Cube | Parametric Sweep]]| style="width:180px;" | Varies the value(s) of one or more project variables| style="width:150px;" | SBR| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Requires definition of sweep variables, works only with SBR solver as the current operational physical scene may change during the sweep |-| style="width:120px;" | [[#Transmitter_Sweep | Transmitter Sweep]]| style="width:180px;" | Activates two or more transmitters sequentially with only one transmitter broadcasting at each simulation run | style="width:150px;" | Polarimatrix| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Requires at least two transmitters in the scene, works only with Polarimatrix solver and running requires an existing ray database|-| style="width:120px;" | [[#Rotational_Sweep | Rotational Sweep]]| style="width:180px;" | Rotates the SBR radiation pattern of the transmit antenna(s) sequentially to model beam steering | style="width:150px;" | Polarimatrix| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Works only with Polarimatrix solver and requires an existing ray database|-| style="width:120px;" | [[#Mobile_Sweep | Mobile Sweep]]| style="width:180px;" | Considers one pair of active transmitter and receiver at each simulation engine run to model a mobile communication link| style="width:150px;" | Polarimatrix| style="width:120px;" | Runs at the center frequency fc| style="width:300px;" | Requires the same number of transmitters and receivers, works only with Polarimatrix solver and requires an existing ray database|} Click on each item in the above list to learn more about each simulation mode.  You set the simulation mode in EM.Terrano's simulation run dialog using the drop-down list labeled '''Simulation Mode'''. A single-frequencyanalysis is a single-run simulation. All the other simulation modes in the above list are considered multi-run simulations. In multi-run simulation modes, certain parameters are varied and a collection of simulation data at all frequency samples files are saved into generated. At the end of a sweep simulation, you can plot the output parameter results on 2D graphs or you can animate the 3D simulation data files including "SBR_results.RTOUT"from the navigation tree.
{{Note| EM.Terrano's frequency sweep simulations are very fast because the geometrical optics (ray tracing) part of the simulation is frequency-independent.}}
[[Image:Info_icon.png|40px]] Click here to learn more about '''[[Parametric_Modeling,_Sweep_%26_Optimization#Running_Parametric_Sweep_Simulations_in_EM.Cube | Running Parametric === Transmitter Sweep Simulations in EM.Cube]]'''.===
== Working When your propagation scene contains two or more transmitters, whether they all belong to the same transmitter set with SBR Simulation Data ==the same radiation pattern or to different transmitter sets, EM.Terrano assumes all to be coherent with respect to one another. In other words, synchronous transmitters are always assumed. The rays originating from all these transmitters are superposed coherently and vectorially at each receiver. In a transmitter sweep, on the other hand, EM.Terrano assumes only one transmitter broadcasting at a time. The result of the sweep simulation is a number of received power coverage maps, each corresponding to a transmitter in the scene.
=== {{Note| EM.Terrano's Output Simulation Data ===transmitter sweep works only with the Polarimatrix Solver and requires an existing ray database previously generated using the Channel Analyzer.}}
At the end of an SBR simulation, all the polarimetric rays emanating from the transmitter(s) or other sources that are received by the individual receivers are computed, collected, sorted and saved. From the ray data, the total electric field at the location of receivers as well as the received power are computed. The ray data include the field components of each ray, the ray's elevation and azimuth angles of departure and arrival (departure from the transmitter location and arrival at the receiver location), and time delay of the received ray with respect to the transmitter. If you specify the temperature, noise figure levels and transmission line losses in the definition of the receiver sets, the noise power level and signal-to-noise ratios (SNR) at each receiver are also calculated. If you define a field sensor, or a far field observable, or a Huygens surface for your project, your output simulation data will include near-field distribution maps, far field radiation patterns or Huygens surface data files, respectively. === Rotational Sweep ===
=== Visualizing Field & Received Power Coverage Maps ===You can rotate the 3D radiation patterns of both the transmitters and receivers from the property dialog of the parent transmitter set or receiver set. This is done in advance before a SBR simulation starts. You can define one or more of the rotation angles of a transmitter set or a receiver set as sweep variables and perform a parametric sweep simulation. In that case, the entire scene and all of its buildings are discretized at each simulation run and a complete physical SBR ray tracing simulation is carried out. However, we know that the polarimetric characteristics of the propagation channel are independent of the transmitter or receiver antenna patterns or their rotation angles. A rotational sweep allows you to rotate the radiation pattern of the transmitter(s) about one of the three principal axes sequentially. This is equivalent to the steering of the beam of the transmit antenna either mechanically or electronically. The result of the sweep simulation is a number of received power coverage maps, each corresponding to one of the angular samples. To run a rotational sweep, you must specify the rotation angle.
As an asymptotic EM simulator, {{Note| EM.Terrano computes 's rotational sweep works only with the polarimetric electric field at every receiver location including amplitude Polarimatrix Solver and phase of all three X, Y, Z field components as well as requires an existing ray database previously generated using the total field magnitudeChannel Analyzer. In wireless propagation modeling for communication system applications, the received power at the receiver location is more important than the field values. Wireless coverage maps commonly refer to the received power levels at different locations in a given site. In order to compute the received power, you need three pieces of information:}}
* '''Total Transmitted Power (EIRP)''': This requires knowledge of the baseband signal power, the transmitter chain [[parameters]], the transmission characteristics of the transmission line connecting the transmitter circuit to the transmitting antenna and the radiation characteristics of the transmitting antenna.* '''Channel Path Loss''': This is computed through SBR simulation. * '''Receiver Properties''': This includes the radiation characteristics of the receiving antenna, the transmission characteristics of the transmission line connecting the receiving antenna to the receiver circuit and the receiver chain [[parameters]].=== Mobile Sweep ===
The received power P<sub>r</sub> In a mobile sweep, each transmitter is paired with a receiver according to their indices in dBm their parent sets. At each simulation run, only one (Tx, Rx) pair is found from considered to be active in the scene. As a result, the generated coverage map takes a different meaning implying the sequential movement of the transmitter and receiver pair along their corresponding paths. In other words, the set of point transmitters and the set of point receivers indeed represent the locations of a single transmitter and a single receiver at different instants of time. It is obvious that the total number of transmitters and total number of receivers in the following equation:scene must be equal. Otherwise, EM.Terrano will prompt an error message.
<math> P_r [dBm[EM.Cube] = P_t ] provides a '''Mobile Path Wizard''' that facilitates the creation of a transmitter set or a receiver set along a specified path. This path can be an existing nodal curve (polyline or NURBS curve) or an existing line objects. You can also import a sptial Cartesian data file containing the coordinates of the base location points. For more information, refer to [dBm[Glossary_of_EM.Cube%27s_Wizards#Mobile_Path_Wizard | Mobile Path Wizard]] + G_{TC} + G_{TA} - PL + G_{RA} + G_{RC} </math>.
where P<sub>t</sub> is the baseband signal power in dBm at the transmitter, G<sub>TC</sub> and G<sub>RC</sub> are the total transmitter and receiver chain gains in dB, respectively, G<sub>TA</sub> and G<sub>RA</sub> are the total transmitting and receiving antenna gains in dB, respectively, and PL is the channel path loss in dB. Keep in mind that {{Note| EM.Terrano is fully polarimetric. The transmitting and receiving antenna characteristics are specified through 's mobile sweep works only with the imported radiation pattern files, which are part of the definition of the transmitters Polarimatrix Solver and receivers. In particular, requires an existing ray database previously generated using the polarization mismatch losses are taken into account through the polarimetric SBR ray tracing analysisChannel Analyzer. }}
EM.Terrano's transmitters always require === Investigating Propagation Effects Selectively One at a radiation pattern file unless you use a short dipole source to excite your structure. On the other hand, EM.Terrano's default receivers are assumed to be isotropic radiators. Although isotropic radiators do not exist as actual physical antennas, they make convenient and useful theoretical observables for the purpose of power coverage map calculations. EM.Terrano's isotropic receiving radiators are assumed to be polarization-matched to the incoming rays. As such, they have a unity gain and do not exhibit any polarization mismatch losses. Time ===
In a typical SBR ray tracing simulation, EM.Terrano includes all the propagation effects such as direct (LOS) rays, ray reflection and transmission, and edge diffractions. At the end of an a SBR simulation, you can visualize the field maps and receiver received power coverage map of your receiver sets. A coverage map shows propagation scene, which appears under the total '''Received Power''' by each of the receivers and is visualized as a color-coded intensity plot. Under each receiver set node item in the navigation tree, a total of seven field maps together with a . The figure below shows the received power coverage map are added. The field maps include amplitude and phase plots for of the three X, Y, Z field components plus random city scene with a total electric field plotvertically polarized half-wave dipole transmitter located 10m above the ground and a large grid of vertically polarized half-wave dipole receivers placed 1. To display a field or coverage map, simply click on its entry in 5m above the navigation treeground. The 3D plot appears in the Main Window overlaid on your propagation scene. A legend box on the right shows the limits of the color scale and units (dB). The 3D coverage maps are displayed map between -23dBm as horizontal confetti above the receivers. You can change the appearance of the receivers maximum and maps from the property dialog of -150dB (the default receiver set. You can further customize sensitivity value) as the settings of the 3D field and coverage plotsminimum.
<table><tr><td> [[Image:Info_iconUrbanCanyon10.png|40px]] Click here to learn more about '''[[Data_Visualization_and_Processing#Visualizing_3D_Near-Field_Maps thumb| Visualizing 3D Near-Field Mapsleft|640px|The received power coverage map of the random city scene with a dipole transmitter.]]'''.</td></tr></table>
At Sometime it is helpful to change the end scale of a frequency sweep or parametric sweep SBR simulation, as many coverage maps as the number of sweep variable samples are generated and added color map to better understand the navigation tree. In this case dynamic range of the additional seven field maps are saved to avoid a cluttered navigation treecoverage map. You can If you double-click on the legend or right-click on each of the coverage maps corresponding to each of map's name in the variable samples navigation tree and visualize it in select '''Properties''', the project workspacePlot Settings dialog opens up. You can also animate Select the coverage maps on '''User-Defined''' item and set the navigation treelower and upper bounds of color map as you wish.
<table><tr><td> [[Image:Info_iconUrbanCanyon15.png|40pxthumb|left|480px|The plot settings dialog of the coverage map.]] Click here to learn more about '''</td></tr></table><table><tr><td> [[Data_Visualization_and_Processing#3D_Near_Image:UrbanCanyon16.26_Far_Field_Animation png| Animating 3D Nearthumb|left|640px|The received power coverage map of the random city scene with a user-Field Mapsdefined color map scale between -80dBm and -20dBm.]]'''</td></tr></table>Â To better understand the various propagation effects, EM.Terrano allows you to enable or disable these effects selectively. This is done from the Ray Tracing Simulation Engine Settings dialog using the provided check boxes.
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<td> [[Image:prop_run11_tnUrbanCanyon14.png|thumb|550pxleft|Received power coverage map of an urban 640px|EM.Terrano's simulation run dialog showing the check boxes for controlling various propagation sceneeffects.]] </td><td> [[Image:prop_run12_tn.png|thumb|550px|Total electric field map of an urban propagation scene.]] </td>
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=== Calculating <table><tr><td> [[Image:UrbanCanyon11.png|thumb|left|640px|The received power coverage map of the SNR & Visualizing Connectivity Maps===random city scene with direct LOS rays only.]] </td></tr><tr><td> [[Image:UrbanCanyon12.png|thumb|left|640px|The received power coverage map of the random city scene with reflected rays only.]] </td></tr><tr><td> [[Image:UrbanCanyon13.png|thumb|left|640px|The received power coverage map of the random city scene with diffracted rays only.]] </td></tr></table>
== Working with EM.Terrano's Simulation Data == === The Ray Tracing Solvers' Output Simulation Data === Both the SBR solver and the Polarimatrix solver perform the same type of simulation but in two different ways. The SBR solver discretizes the scene including all the buildings and terrain, shoots a large number of rays from the transmitters and collects the rays at the receivers. The Polarimatrix solver does the same thing using an existing polarimetric ray database that has been previously generated using EM.Terrano's Channel Analyzer. It incorporates the effects of the radiation patterns of the transmit and receive antennas in conjunction with the polarimetric channel characteristics. At the end of a ray tracing simulation, all the polarimetric rays emanating from the transmitter(s) or other sources that are received by the individual receivers are computed, collected, sorted and saved into ASCII data files. From the ray data, the total electric field at the location of receivers as well as the total received power are computed. The individual ray data include the field components of each ray, the ray's elevation and azimuth angles of departure and arrival (departure from the transmitter location and arrival at the receiver location), and time delay of the received ray with respect to the transmitter. If you specify the temperatures, noisefigure and transmission line losses in the definition of the receiver sets, the noise power level and signal-related to-noise ratio (SNR) at each receiver are also calculated, and so are the E<sub>b</sub>/N<sub>0</sub> and bit error rate (BER) for the selected digital modulation scheme. === Visualizing Field & Received Power Coverage Maps === In wireless propagation modeling for communication system applications, the received power at the receiver location is more important than the field distributions. In order to compute the received power, you need three pieces of information: * '''Total Transmitted Power (EIRP)''': This requires knowledge of the baseband signal power, the transmitter chain parameters, the transmission characteristics of the transmission line connecting the transmitter circuit to the transmitting antenna and the radiation characteristics of the transmitting antenna.* '''Channel Path Loss''': This is computed through SBR simulation. * '''Receiver Properties''': This includes the radiation characteristics of the receiving antenna, the transmission characteristics of the transmission line connecting the receiving antenna to the receiver circuit and the receiver chain parameters. In a simple link scenario, the received power P<sub>r</sub> in dBm is found from the following equation: <math> P_r [dBm] = P_t [parameters]dBm] + G_{TC} + G_{TA} - PL + G_{RA} + G_{RC} </math> where P<sub>t</sub> is the baseband signal power in dBm at the transmitter, G<sub>TC</sub> and G<sub>RC</sub> are the total transmitter and receiver chain gains in dB, respectively, G<sub>TA</sub> and G<sub>RA</sub> are the total transmitting and receiving antenna gains in dB, respectively, and PL is the channel path loss in dB. Keep in mind that EM.Terrano is fully polarimetric. The transmitting and receiving antenna characteristics are specified through the imported radiation pattern files, which are part of the definition of the transmitters and receivers. In particular, the polarization mismatch losses are taken into account through the polarimetric SBR ray tracing analysis.  If you specify the noise-related parameters of your receiver set, the signal-to-noise ratios (SNR) is calculated at each receiver location: SNR = P<sub>r</sub> - P<sub>n</sub>, where P<sub>n</sub> is the noise power level in dB. When planning, designing and deploying a communication system between points A and B, the link is considered to be closes and a connection established if the received signal power at the location of the receiver is above the noise power level by a certain threshold. In other words, the SNR at the receiver must be greater than a certain specified minimum SNR level. You specify (SNR)<sub>min</sub> ss part of the definition of receiver chain in the Receiver Set dialog. In the "Visualization Options" section of this dialog, you can also check the check box labeled '''Generate Connectivity Map'''. This is a binary-level black-and-white map that displays connected receivers in white and disconnected receivers in black. At the end of an SBR simulation, the computed SNR is displayed in the Receiver Set dialog for the selected receiver. The connectivity map is generated and added to the navigation tree underneath the received power coverage map node.  At the end of an SBR simulation, you can visualize the field maps and receiver power coverage map of your receiver sets. A coverage map shows the total '''Received Power''' by each of the receivers and is visualized as a color-coded intensity plot. Under each receiver set node in the navigation tree, a total of seven field maps together with a received power coverage map are added. The field maps include amplitude and phase plots for the three X, Y, Z field components plus a total electric field plot. To display a field or coverage map, simply click on its entry in the navigation tree. The 3D plot appears in the Main Window overlaid on your propagation scene. A legend box on the right shows the color scale and units (dB). The 3D coverage maps are displayed as horizontal confetti above the receivers. You can change the appearance of the receivers and maps from the property dialog of the receiver set. You can further customize the settings of the 3D field and coverage plots.
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<td> [[Image:PROP15AAnnArbor Scene1.png|thumb|550pxleft|640px|The downtown Ann Arbor propagation scene.]]</td></tr><tr><td>[[Image:AnnArbor Scene2.png|thumb|left|640px|The electric field distribution map of the Ann Arbor scene with vertical dipole transmitter and receivers.]]</td></tr><tr><td>[[Image:AnnArbor Scene3.png|thumb|left|640px|The received power coverage map of the Ann Arbor scene with vertical dipole transmitter and receivers.]]</td></tr><tr><td>[[Image:AnnArbor Scene4.png|thumb|left| 640px |The connectivity map of an urban propagation the Ann Arbor scene with minimum SNR level set to 25dB<sub>min</sub> = 3dB with the basic color map option.]]</td></tr><tr><td>[[Image:AnnArbor Scene5.png|thumb|left| 640px |The connectivity map of the Ann Arbor scene with SNR<sub>min</sub> = 20dB with the basic color map option.]] </td>
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=== Visualizing the Rays in the Scene ===
[[Image:PROP12B.png|thumb|420px|EM.Terrano's Ray Data dialog.]]
At the end of a SBR simulation, each receiver receives a number of rays. Some receivers may not receive any rays at all. You can visualize all the rays received by a certain receiver from the active transmitter of the scene. To do this, right click the '''Receivers''' item of the Navigation Tree. From the context menu select '''Show Received Rays'''. All the rays received by the currently selected receiver of the scene are displayed in the scene. The rays are identified by labels, are ordered by their power and have different colors for better visualization. You can display the rays for only one receiver at a time. The receiver set property dialog has a list of all the individual receivers belonging to that set. To display the rays received by another receiver, you have to change the '''Selected Receiver''' in the receiver set's property dialog. If you keep the mouse focus on this dropdown list and roll your mouse scroll wheel, you can scan the selected receivers and move the rays from one receiver to the next in the list. To remove the visualized rays from the scene, right click the Receivers item of the Navigation Tree again and from the context menu select '''Hide Received Rays'''.
You can also view the ray [[parameters]] by opening the property dialog of a receiver set. By default, the first receiver of the set is always selected. You can select any other receiver from the drop-down list labeled '''Selected Receiver'''. If you click the button labeled '''Show Ray Data''', a new dialog opens up with a table that contains all the received rays at the selected receiver and their [[parameters]]:
* Delay is the total time delay that a ray experiences travelling from the transmitter to the receiver after all the reflections, transmissions and diffractions and is expressed in nanoseconds.
* Ray Power is the received power at the receiver due to a specific ray and is given in dBm.
* Angles of Arrival are the θ and φ angles of the incoming ray at the local spherical coordinate system of the receiver.
Â
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[[Image:UrbanCanyon17.png|thumb|left|720px|EM.Terrano's ray data dialog showing a selected ray.]]
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The Ray Data Dialog also shows the '''Total Received Power''' in dBm and '''Total Received Field''' in dBV/m due to all the rays received by the receiver. You can sort the rays based on their delay, field, power, etc. To do so, simply click on the grey column label in the table to sort the rays in ascending order based on the selected parameter. You can also select any ray by clicking on its '''ID''' and highlighting its row in the table. In that case, the selected rays is highlighted in the Project Workspace and all the other rays become thin (faded).
<table>
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<td> [[Image:prop_run5_tnUrbanCanyon18.png|thumb|550pxleft|640px|Visualization of received rays at the location of the a selected receiver.]] </td><td> [[Image:prop_run6_tn.png|thumb|550px|Analyzing a selected ray from in the ray data dialograndom city scene.]] </td>
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=== The Standard Output Data Files File ===
[[Image:prop_run8_tn.png|thumb|800px|A typical SBR output data file.]]At the end of an SBR simulation, EM.Terrano writes a number of ASCII data files to your project folder. The main output data file is called "sbr_results.RTOUT". This file contains all the information about individual receivers and the [[parameters]] of each ray that is received by each individual receiver.
At the end of an SBR simulation, the results are written into a main output data file with the reserved name of SBR_Results.RTOUT. This file has the following format:
The angles of arrival are the θ and φ angles of a received ray measured in degrees and are referenced in the local spherical coordinate systems centered at the location of the receiver. The angles of departure for a received ray are the θ and φ angles of the originating transmitter ray, measured in degrees and referenced in the local spherical coordinate systems centered at the location of the active transmitter, which eventually arrives at the receiver. The total time delay is measured in nanoseconds between t = 0 nsec at the time of launch from the transmitter location till being received at the receiver location.
Â
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[[Image:prop_run8_tn.png|thumb|left|720px|A typical SBR output data file.]]
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=== Plotting Other Simulation Results ===
Besides "sbr_results.out", [[EM.Terrano ]] writes a number of other ASCII data files to your project folder. You can view or plot these data in [[EM.Cube]]'s Data Manager. You can open data manager by clicking the '''Data Manager''' [[File:data_manager_icon.png]] button of the '''Simulate Toolbar''' or by selecting '''Menu > Simulate > Data Manager''' from the menu bar or by right-clicking on the '''Data Manager''' item of the navigation tree and selecting '''Open Data Manager...''' from the contextual menu or by using the keyboard shortcut {{key|Ctrl+D}}.
The available data files in the "2D Data Files" tab of Data Manger include:
* '''Angles of Arrival''': These are the Theta and Phi angles of the individual rays received by the selected receiver and saved to the files "SBR_receiver_set_name_ThetaARRIVAL.ANG" and "SBR_receiver_set_name_PhiARRIVAL.ANG". You can plot them in the Data Manager in polar stem charts.
When you run a frequency or parametric sweep in [[EM.Terrano]], a tremendous amount of data may be generated. [[EM.Terrano ]] only stores the '''Received Power''', '''Path Loss''' and '''SNR''' of the selected receiver
in ASCII data files called "PREC_i.DAT", "PL_i.DAT" and "SNR_i.DAT", where is the index of the receiver set in your scene. These quantities are tabulated vs. the sweep variable's samples. You can plot these files in EM.Grid.
[[Image:Info_icon.png|40px]] Click here to learn more about working with data filed and plotting graphs in [[EM.Cube]]'s '''[[Data_Visualization_and_ProcessingDefining_Project_Observables_%26_Visualizing_Output_Data#Working_with_Data_Files_in_Data_ManagerThe_Data_Manager | Data Manager]]'''.
<table>
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<td> [[Image:PROP20ETerrano pathloss.png|thumb|350px360px|Cartesian graph of path loss.]] </td><td> [[Image:PROP20FTerrano delay.png|thumb|350px360px|Bar graph of power delay profile.]] </td>
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<td> [[Image:PROP20GTerrano ARR phi.png|thumb|350px360px|Polar stem graph of Phi angle of arrival.]] </td><td> [[Image:PROP20HTerrano ARR theta.png|thumb|350px360px|Polar stem graph of Theta angle of arrival.]] </td></tr><tr><td> [[Image:Terrano DEP phi.png|thumb|360px|Polar stem graph of Phi angle of departure.]] </td><td> [[Image:Terrano DEP theta.png|thumb|360px|Polar stem graph of Theta angle of departure.]] </td></tr></table>Â === Visualizing 3D Radiation Patterns of Transmit and Receive Antennas in the Scene ===Â When you designate a "User Defined Antenna Pattern" as the radiator type of a transmitter set or a receiver set, EM.Terrano copies the imported radiation pattern data file from its original folder to the current project folder. The name of the ".RAD" file is listed under the '''3D Data Files''' tab of the data manager. Sometimes it might be desired to visualize these radiation patterns in your propagation scene at the actual location of the transmitter or receiver. To do so, you have to define a new '''Radiation Pattern''' observable in the navigation tree. The label of the new observable must be identical to the name of the ".RAD" data file. In addition, the Theta and Phi angle increments of the new radiation pattern observable (expressed in degrees) must be identical to the Theta and Phi angular resolutions of the imported pattern file. If all these conditions are met, then go to the '''Simulate Menu''' and select the item '''Update All 3D Visualization'''. The contents of the 3D radiation patterns are added to the navigation tree. Click on one of the radiation pattern items in the navigation tree and it will be displayed in the scene. Â <table><tr><td>[[Image:UrbanCanyon6.png|thumb|left|640px|The received power coverage map of the random city scene with a highly directional dipole array transmitter.]]</td></tr></table>Â By Default, [[EM.Cube]] always visualizes the 3D radiation patterns at the origin of coordinates, i.e. at (0, 0, 0). This is because that radiation pattern data are computed in the standard spherical coordinate system centered at (0, 0, 0). The theta and phi components of the far-zone electric fields are defined with respect to the X, Y and Z axes of this system. When visualizing the 3D radiation pattern data in a propagation scene, it is more intuitive to display the pattern at the location of the transmitter or receiver. The Radiation Pattern dialog allows you to translate the pattern visualization to any arbitrary point in the project workspace. It also allows you to scale up or scale down the pattern visualization with respect to the background scene. Â In the example shown above, the imported pattern data file is called "Dipole_Array1.RAD". Therefore, the label of the radiation pattern observable is chosen to be "Dipole_Array1". The theta and phi angle increments are both 1° in this case. The radiation pattern has been elevated by 10m to be positioned at the location of the transmitter and a scaling factor of 0.3 has been used. Â <table><tr><td>[[Image:UrbanCanyon8.png|thumb|left|640px|Setting the pattern parameters in the radiation pattern dialog.]]</td></tr></table><table><tr><td>[[Image:UrbanCanyon7.png|thumb|left|720px|Visualization of the 3D radiation pattern of the directional transmitter in the random city scene.]]</td></tr></table>Â There is an important catch to remember here. When you define a radiation pattern observable for your project, EM.Terrano will attempt to compute the overall effective radiation pattern of the entire physical structure. However, in this case, you defined the radiation pattern observable merely for visualization purposes. To stop EM.Terrano from computing the actual radiation pattern of your entire scene, there is a check box in EM.Terrano's Ray Tracer Simulation Engine Settings dialog that is labeled '''Do not compute new radiation patterns'''. This box is checked by default, which means the actual radiation pattern of your entire scene will not be computed automatically. But you need to remember to uncheck this box if you ever need to compute a new radiation pattern using EM.Terrano's SBR solver as an asymptotic EM solver (see next section). Â <table><tr><td>[[Image:UrbanCanyon9.png|thumb|left|640px|EM.Terrano's Run Simulation dialog.]]</td></tr></table>Â == Using EM.Terrano as an Asymptotic Field Solver ==Â Like every other electromagnetic solver, EM.Terrano's SBR ray tracer requires an excitation source and one or more observables for the generation of simulation data. EM.Terrano offers several types of sources and observables for a SBR simulation. You already learned about the transmitter set as a source and the receiver set as an observable. You can mix and match different source types and observable types depending on the requirements of your modeling problem. Â The available source types in EM.Terrano are:Â {| class="wikitable"|-! scope="col"| Icon! scope="col"| Source Type! scope="col"| Applications! scope="col"| Restrictions|-| style="width:30px;" | [[File:transmitter_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Point Transmitter Set | Point Transmitter Set]]| style="width:250px;" | Modeling realsitic antennas & link budget calculations| style="width:250px;" | Requires to be associated with a base location point set|-| style="width:30px;" | [[File:hertz_src_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Hertzian Short Dipole Source | Hertzian Short Dipole]]| style="width:250px;" | Almost omni-directional physical radiator| style="width:250px;" | None, stand-alone source|-| style="width:30px;" | [[File:huyg_src_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types#Huygens Source | Huygens Source]]| style="width:250px;" | Used for modeling equivalent sources imported from other [[EM.Cube]] modules | style="width:250px;" | None, stand-alone source imported from a Huygens surface data file|}Â Click on each type to learn more about it in the [[Glossary of EM.Cube's Materials, Sources, Devices & Other Physical Object Types]]. Â The available observables types in [[EM.Terrano]] are:Â {| class="wikitable"|-! scope="col"| Icon! scope="col"| Source Type! scope="col"| Applications! scope="col"| Restrictions|-| style="width:30px;" | [[File:receiver_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables & Graph Types#Point Receiver Set | Point Receiver Set]]| style="width:250px;" | Generating received power coverage maps & link budget calculations| style="width:250px;" | Requires to be associated with a base location point set|-| style="width:30px;" | [[File:Distr Rx icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables & Graph Types#Distributed Receiver Set | Distributed Receiver Set]]| style="width:250px;" | Computing received power at a receiver characterized by Huygens surface data| style="width:250px;" | None, stand-alone source imported from a Huygens surface data file|-| style="width:30px;" | [[File:fieldsensor_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables & Graph Types#Near-Field Sensor Observable | Near-Field Sensor]]| style="width:250px;" | Generating electric and magnetic field distribution maps| style="width:250px;" | None, stand-alone observable|-| style="width:30px;" | [[File:farfield_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables & Graph Types#Far-Field Radiation Pattern Observable | Far-Field Radiation Pattern]]| style="width:250px;" | Computing the effective radiation pattern of a radiator in the presence of a large scattering scene | style="width:250px;" | None, stand-alone observable|-| style="width:30px;" | [[File:huyg_surf_icon.png]]| style="width:150px;" | [[Glossary of EM.Cube's Simulation Observables & Graph Types#Huygens Surface Observable | Huygens Surface]]| style="width:250px;" | Collecting tangential field data on a box to be used later as a Huygens source in other [[EM.Cube]] modules| style="width:250px;" | None, stand-alone observable|}Â Click on each type to learn more about it in the [[Glossary of EM.Cube's Simulation Observables & Graph Types]]. When you define a far-field observable in EM.Terrano, a collection of invisible, isotropic receivers are placed on the surface of a large sphere that encircles your propagation scene and all of its geometric objects. These receivers are placed uniformly on the spherical surface at a spacing that is determined by your specified angular resolutions. In most cases, you need to define angular resolutions of at least 1° or smaller. Note that this is different than the transmitter rays' angular resolution. You may have a large number of transmitted rays but not enough receivers to compute the effective radiation pattern at all azimuth and elevation angles. Also keep in mind that with 1° Theta and Phi angle increments, you will have a total of 181 × 361 = 65,341 spherically placed receivers in your scene. Â {{Note| Computing radiation patterns using EM.Terrano's SBR solver typically takes much longer computation times than using [[EM.Cube]]'s other computational modules.}} <table><tr><td> [[Image:SBR pattern.png|thumb|540px|Computed 3D radiation pattern of two vertical short dipole radiators placed 1m apart in the free space at 1GHz.]] </td>
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=== Statistical Analysis of Propagation Scene ===
[[Image:PROP12A.png|thumb|400px|EM.Terrano's Simulation Run dialog showing frequency sweep as the simulation mode along with statistical analysis.]]
EM.Terrano's coverage maps display the received power at the location of all the receivers. The receivers together from a set/ensemble, which might be uniformly spaced or distributed across the propagation scene or may consist of randomly scattered radiators. Every coverage map shows the '''Mean''' and '''Standard Deviation''' of the received power for all the receivers involved. These information are displayed at the bottom of the coverage map's legend box and are expressed in dB.
When you run either a frequency sweep or a parametric sweep simulation in EM.Terrano, you have the option to generate two additional coverage maps: one for the mean of all the individual sample coverage maps and another for their standard deviation. To do so, in the '''Run Dialog''', check the box labeled '''"Create Mean and Standard Deviation Coverage Mapsreceived power coverage maps"'''. Note that the mean and standard deviation values displayed on the individual coverage maps correspond to the spatial statistics of the receivers in the scene, while the mean and standard deviation coverage maps show the statistics with respect to the frequency or other sweep variable sets at each point in the site. Also, note that both of the mean and standard deviation coverage maps have their own spatial mean and standard deviation values expressed in dB at the bottom of their legend box.
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<td> [[Image:prop_run21_tnPROP MAN12.png|thumb|400pxleft|The mean coverage map at the end of a 480px|EM.Terrano's simulation run dialog showing frequency sweepas the simulation mode along with statistical analysis.]] </td><td> [[Image:prop_run22_tn.png|thumb|400px|The standard deviation coverage map at the end of a frequency sweep.]] </td>
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<ptable> <tr><td> [[Image:UrbanCanyon4.png|thumb|left|640px|The mean coverage map at the end of a frequency sweep.]] </ptd></tr><tr><td>[[Image:UrbanCanyon5.png|thumb|left|640px|The standard deviation coverage map at the end of a frequency sweep.]] </td></tr></table>Â <br />Â <hr>Â [[Image:Top_icon.png|48px30px]] '''[[EM.Terrano#An_EM.Terrano_Primer Product_Overview | Back to the Top of the Page]]'''Â [[Image:Tutorial_icon.png|30px]] '''[[EM.Cube#EM.Terrano_Documentation | EM.Terrano Tutorial Gateway]]'''
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