RF Channel Modeler Analysis Tab
After generating your transceivers under the Design tab, you can then set up the remaining simulation parameters under the Analysis tab. This tab has three sections that cover the following functionality:
- Analysis configuration - In the top section, you need to create one or more analysis configurations to run.
- Configuration specification - For each analysis configuration, use the following tabs to set the specifications:
- Output - At the bottom of the Analysis tab, you can select the output folder and then run the highlighted analysis configuration.
Analysis configuration
Use this top panel to instantiate all your analysis configurations. This includes specifying settings with the Analysis Extent Tool and Advanced Solver Options dialog box. As you add analysis configurations, their names appear in the list along with the configuration status of each.
You can add or remove analysis configurations using the following icons.
| Option | Icon | Description |
|---|---|---|
| Add Configuration |
|
When you click this icon, choose one of the following configuration types:
When the Add Configuration dialog box appears, enter a name for the analysis configuration and click . |
| Delete Configuration |
|
To remove an analysis configuration from the list, select (highlight) it and click . |
| Duplicate Configuration |
|
To duplicate an analysis configuration in the list, select (highlight) it and click . The Duplicate Configuration dialog box appears. Enter a name for the duplicated analysis configuration, or retain the default name, and click . The new analysis configuration now appears in the list. |
Analysis Extent Tool
When you click the Analysis Extent Tool icon (
) in the top panel, the Analysis Extent Tool dialog box appears, enabling you to adjust the physical extent of the analysis area. The tool lists all the analysis configurations available. Use the following parameters in the dialog box to specify the extent.
| Item | Description |
|---|---|
| Select All | Select this check box to apply your extents adjustments to all of the analysis configurations listed in the dialog box. |
| Select | A check box is available for each analysis configuration. Select the check boxes for the ones you want to include in the extents adjustment. |
| 3D Window Selection - Enable | This Enable check box defaults to selected, which enables you to go to the 3D Graphics window and click and drag the extent boundary to adjust it. |
| Northwest Latitude, Northwest Longitude, Southeast Latitude, Southeast Longitude | Enter values for each of these, in degrees, to specify the northwest and southeast corners of the analysis region. |
After you set all the parameters in the table, click to make all the adjustments.
Advanced Solver Options
When you click the Advanced Solver Options icon (
) in the top panel, the Advanced Solver Options dialog box appears, enabling you to adjust the settings for the scattering and bouncing rays algorithm for all of the analysis configurations. The table lists all available settings. When you are finished, click to apply your settings and close the dialog box.
| Setting | Description |
|---|---|
| Enable Geometrical Optics Blockage |
The basic SBR+ ray tracing model uses rays only to paint direct currents on the scattering geometry. If you select this check box, the algorithm also computes the following:
If you select the check box, you can choose a Starting Bounce value, either 0 or 1. The default is 1. Starting Bounce is the bounce at which the geometrical optics blockage checks start. Setting the value to 0 also applies geometrical optics blockage checks to the coupling incident field, effectively computing geometrical optics-style direct field instead. |
| Ray Density |
This is a setting for specifying the density of rays as they pass through a sampling box at a given distance from the source. Ansys recommends that you retain the default setting or contact product support for assistance in adjusting this parameter. |
| Maximum Number of Reflections | Enter the maximum number of times that the RF Channel Modeler algorithm will allow a ray to reflect off of an object or facet. |
| Maximum Number of Transmissions | This is the maximum number of penetrable surfaces that the algorithm allows a ray to traverse before ending that ray's track processing. |
| Bounding Box |
This setting limits the area for solver meshing and processing computations to the box window around a target region. Choose one of the following options:
|
Configuration specification
In the Analysis tab, there are two middle panels. The left panel shows all the applicable STK objects and all the RF Channel Modeler transceivers you added. Use the subtabs in the right panel to set the specifics for the analysis configuration that you highlighted in the top Analysis panel.
Transceivers subtab
Click the Add Transceiver icon () to select transceivers to include in the analysis configuration. When you click the icon, the Add Configuration Analysis Transceivers dialog box appears. You can enable the Select All check box to include all the available transceivers, or you can select individual transceivers by marking the Select check box next to the ones you want. If your Analysis Configuration is a Communications type, then only Communication type transceivers (
) are available. If your Analysis Configuration is a Radar type, then only Radar type transceivers (
) are available. For all selected transceivers, you can change them from the default Transceive Mode to TransmitOnly or ReceiveOnly using the Mode drop-down menu. Then click to apply the selections and close the dialog box.
After including transceivers, you will see them listed in the Transceivers tab. For each transceiver listed, you can see its name, STK Sensor object path, and associated central body. These are read-only parameters. You can select the Include Parent Facets check box to have the RF Channel Modeler include these facets in the calculations. You can also change the Mode from this list.
To delete a transceiver from the list, select (highlight) it in the list and click the Remove Transceiver icon ().
Scene Contributor Objects subtab
Click the Add Scene Contributor icon () to add available STK objects to the analysis calculations. When you click the icon, the Add Analysis Scene Contributors dialog box appears, enabling you to select objects individually or all at once, using the Select All check box. You can remove an object by highlighting it in the list and clicking the Remove Scene Contributor icon (). Each scene contributor object shows its associated central body.
The RF Channel Modeler will check to assure that, for each object you add as a contributor, the object's model in STK is type GLB or glTF. This ensures that the model provides surface facets; otherwise, the analysis computation will fail.
Analysis Compute Times subtab
Use this subtab to specify a total analysis interval as well as the step size for analysis calculations. The subtab provides the following settings:
| Setting | Description |
|---|---|
| Use Scenario Analysis Interval | This check box defaults to selected, which means the analysis calculations will span the entire scenario interval. If you clear this check box, you can specify the analysis interval using the Start Time and Stop Time settings below. |
| Start Time | If you are not using the scenario interval, then enter this time in epoch seconds. |
| Stop Time | If you are not using the scenario interval, then enter this time in epoch seconds. |
| Continuous Channel Soundings | Select this radio button to generate continuous sounding intervals for the entire scenario interval. Thus, the sounding frequency depends on the soundings time step and the number of soundings per time step. This is only available for Communications analysis configurations. |
| Step Size | When you select this radio button, you can enter an analysis step size in seconds or retain the default step size. |
| Step Count | When you select this radio button, you can enter the total number of steps in the analysis interval. |
The last three parameters (Continuous Channel Soundings, Step Size, and Step Count) are mutually exclusive. The default is Continuous Channel Soundings for Communications and Step Size for Radar.
Facet Tileset subtab
Facet tilesets represent the structures in the analysis region that can impact the transmitted energy of the channel soundings. Use this tab to specify both analysis extents and facet tilesets.
The Analysis Extent section shows the current extents, which are the latitude and longitude of the northwest and southeast corners. You can click to use the Analysis Extent Tool to adjust these extents. You can also select the central body for which the extents apply; the default is to use the central body of the STK scenario.
The Analysis Extent Graphics section enables you to specify the graphics for the selected analysis cofiguration. You can adjust the following settings:
| Setting | Description |
|---|---|
| Show Extent | Select this check box to have STK show the analysis extent in both the 2D and 3D Graphics windows. Selecting this check box activates the remaining settings below. |
| Select Color | Click to see the Color dialog box, from which you can choose a different color for the extent. The current extent color appears to the left of the button. |
| Show 3D Label | When selected, the 3D Graphics window displays the name of the analysis configuration for the extent area. |
| Show 2D Label | When selected, the 2D Graphics window displays the name of the analysis configuration for the extent area. |
| Translucency | Enter a number from 0.0 to 1.0 to specify the degree of translucency of the extent region. A value of 1.0 makes the region completely opaque. |
| Top Altitude | Enter a value, in meters, for the highest altitude point to display in the extent region. |
| Bottom Altitude | Enter a value, in meters, for the lowest altitude point to display in the extent region. |
To select one or more tilesets for inclusion in the analysis configuration, first look at the Available Tilesets list at the bottom left of the tab. To be sure this is the most current list, click . Select one or more tilesets and move them to the Selected Tilesets list using . You can also return selected tilesets back to the Available Tilesets list using . Each tileset in the list shows the central body to which it applies. To hide the tilesets that have a central body different than the one for the current analysis configuration, select the check box for Hide tilesets with incompatible central bodies. This check box defaults to selected. If you choose to apply a tileset from another central body, you will get a warning message asking if you want to continue.
For each selected tileset, choose a material to represent its reflective characteristics using the drop-down in the Material column. The installed choices are Metal, Absorber, Glass, and Asphalt. You can create additional choices by adding a JSON file to your STK scenario folder. See Custom 3D Tileset Materials.
Imaging Data Products subtab (Radar only)
In the Imaging Data Products tab, first select the Link Name for the link that you want to specify. The specify the Imaging Data Product Properties.
The following parameters appear on the left side of the subtab:
| Parameter | Description |
|---|---|
| Range Resolution (m) | Defines the desired smallest spacing that can be resolved from two scattering sources in range. This is directly related to the radar bandwidth. |
| Range Window Size (m) | Defines the desired image window extent in range. You should set this to a number that is larger than the largest extent of the target/scene. |
| Cross Range Resolution (m) | Defines the desired smallest spacing that can be resolved from two scattering sources in cross-range (related to Doppler). This is directly related to the number of pulses selected for data processing (related to the collection total angular extent). |
| Cross Range Window Size (m) | Defines the desired image window extent in cross-range (related to Doppler). You should set this to a number that is larger than the largest extent of the target/scene. |
| Required Bandwidth (MHz) | This is a calculated field defined by the desired range resolution parameter. It is the minimum bandwidth necessary to achieve the desired range resolution. This is a read-only parameter. |
| Collection Angle (deg) | This is a calculated field defined by the desired cross-range resolution parameter. It is the minimum bandwidth necessary to achieve the desired cross-range resolution. This is a read-only parameter. |
| Frequency Samples / Pulse | This is a calculated field defined by the desired range window size. This ensures that the image will have no range ambiguities due to data processing wrap-around. This is a read-only parameter. |
| Minimum Pulse Count | This is a calculated field defined by the desired cross-range window size. This ensures that the image will have no cross-range ambiguities due to data processing wrap-around. This is a read-only parameter. |
The following parameters appear under the Enable Sensor Fixed Distance check box. Select the check box to set the first two.
| Parameter | Description |
|---|---|
| Desired Sensor Fixed Distance (m) | This is the desired approximate fixed distance for collection to ensure pulse alignment resulting in a centered image. This overrides the scenario distances. |
| Center Image in Range Window | This check box defaults to selected, meaning that the plots for this analysis configuration will have the image centered in the Range Window that you specify. |
| Distance to Range Window Start (m) | This is the calculated range to the beginning of the image window, based on the desired sensor fixed distance. This is a read-only parameter. |
| Distance to Range Window Center (m) | This is the calculated range to the center of the image window. This is a read-only parameter. |
When you select the Enable Range-Doppler check box, you can specify the following parameters:
| Parameter | Description |
|---|---|
| Range Pixel Count | This defines the image pixel resolution in range (display only). It should always be greater than the frequency samples per pulse parameter. |
| Range Window Type |
These are signal processing windowing choices. Choose one of the following options:
Flat effectively truncates the data with a square wave. This introduces high-frequency Inverse Fast Fourier Transform (IFFT) artifacts in single-pulse processing that appear as 13 dB sidelobes. The other choices are popular windowing options to help reduce these sidelobes. |
| Range Window Side Lobe Level (dB down) | Enter the value in dB. The default is 1. |
| Velocity Pixel Count | This defines the image pixel resolution in cross-range (display only). It should always be greater than the minimum pulse count parameter. |
| Velocity Window Type |
These are signal processing windowing choices. Choose one of the following options:
Flat effectively truncates the data with a square wave. This introduces high-frequency Inverse Fast Fourier Transform (IFFT) artifacts in single-pulse processing that appear as 13 dB sidelobes. The other choices are popular windowing options to help reduce these sidelobes. |
| Velocity Window Side Lobe Level (dB down) | Enter the value in dB. The default is 1. |
When you select the Enable Range-Doppler check box, your only plotting option on the Results tab will be a Range-Doppler image of the transceivers in the Link at each time step.
Results Output tab
Click to write an Analysis Description to go with the numerical results of the analysis. Use the Results File Mode drop-down menu to choose the file generation method: single file or one file per link.
Output
At the bottom of the Analysis tab, designate where the RF Channel Modeler sends the results by specifying the Analysis Output Folder path. You can enter a file path or click to browse to a folder to select.
Run an analysis configuration
When you have finished all setup for an analysis configuration, click at the bottom of the Analysis tab to produce a set of results. You can then go to the Results tab to view these results.