Changes

EM.Terrano

532 bytes added, 18:56, 24 July 2015
/* SBR Simulation Parameters */
You can adjust the mesh resolution and increase the geometric fidelity of discretization by creating more and finer triangular facets. On 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. To adjust the mesh resolution, open the Mesh Settings Dialog by clicking the '''Mesh Settings''' [[File:mesh_settings.png]] button of the Simulate Toolbar or select '''Simulate > Discretization >''' '''Mesh Settings...'''. This dialog provides a single [[parameters]]: '''Edge Mesh Cell Size''', which has a default value of 100 project units. If you are already in the Mesh View Mode and open the Mesh Settings Dialog, you can see the effect of changing the mesh cell size using the {{key|Apply}} button.
Some additional mesh [[parameters]] can be accessed by clicking the {{key|Tessellation Options}} button of the dialog. In the Tessellation Options dialog, you can change the '''Curvature Angle Tolerance''' expressed in degrees, which has a default value of 45°. This parameter can affect the shape of the mesh especially in the case of [[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|[[Solid Objects|solid objects]]]]]]]]]]]]]]]]]]]]]]]]]]]]]] with curved surfaces. Note that unlike [[EM.Cube]]'s other computational modules that express the default mesh density based on the wavelength, the resolution of the SBR mesh generator is expressed in project length units. The default mesh cell size of 100 units might be too large for non-flat objects. You may have to use a smaller mesh cell size along with a lower curvature angle tolerance value to capture the curvature of your curved structures adequately.
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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.
You can also set the '''Angular Resolution''' of the transmitter rays in degrees. By default, every transmitter emanates equi-angular ray tubes at a resolution of 1 degree. Lower angular resolutions larger than 1° speed up the SBR simulation significantly, but they may compromise the accuracy. Higher angular resolutions less than 1° increase the accuracy of the simulating results, but they also increase the computation time. 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 of your computational domain as well as the SBR mesh resolution. To see this value, you have to generate the SBR mesh first. Keeping the angular resolution of your project above this threshold value makes sure that the small mesh facets at very large distances from the source would not miss any impinging ray tubes during the simulation.
=== Running A SBR Frequency Sweep ===
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