Satellite Link Budget Analyzer

Analyze static and time-varying link budgets for satellite communications

Since R2021a

Description

The Satellite Link Budget Analyzer app enables you to analyze static and time-varying link budgets for satellite communications.

Using the app, you can:

• Analyze link budgets by specifying input properties related to the location, transmitter, and receiver characteristics of satellites and ground stations, as well as atmospheric conditions for links.

• Design a satellite communications link to meet a minimum link margin requirement.

• Analyze a time-varying satelliteScenario imported from a MAT file or directly from MATLAB^® workspace.

• Gain insight into intermediate link budget computations.

• Calculate, compare, and visualize results in 2-D and 3-D across a sweep of multiple parameterized design constraints.

For more information, see Get Started with Satellite Link Budget Analyzer App.

Open the Satellite Link Budget Analyzer App

MATLAB Toolstrip: On the Apps tab, under Signal Processing and Communications, click the app icon.

MATLAB Command Prompt: Enter satelliteLinkBudgetAnalyzer.

Examples

Show Default Static Link Budget App Configuration

This example shows the default configuration that appears when you choose the static link budget analyzer at the Satellite Link Budget Analyzer app launch. The figure shows the displayed results and plots, which analyze the default satellite communications link.

The upper-left pane of the app shows the Link Canvas tab, which displays this default configuration:

• Link L1 is an uplink connecting ground station G1 to satellite S1

• Link L3 is a crosslink connecting satellite S3 to satellite S4

• Link L2 is a downlink connecting satellite S2 to ground station G2

The lower-left pane of the app shows the Ground Station, Link, and Satellite tabs. In these tabs, you can adjust the property settings for each entity in the configured links. To view or adjust the property settings of an entity, bring that entity into focus by selecting it in the Link Canvas tab.

The center pane of the app shows the computed link budget results in the Link Budget tab.

The right pane of the app window shows these plots:

• Free-space path loss for links L1, L2, and L3 in the upper-right area (FSPL tab).

• Link margins for links L1, L2, and L3 in separate tabbed plots in the lower-right area (Margin-L1, Margin-L2, and Margin-L3 tabs, respectively).

The app accepts MATLAB® workspace variables and function calls.

Configuration Including P.618 Link Availability Analysis

The app supports analyzing the satellite communications link availability through the propagation loss model defined in Recommendation ITU-R P.618. For details on the P.618 propagation loss model, see Earth-Space Propagation Losses.

To include ITU-R P.618 propagation losses for availability analysis, select the Include P.618 Losses checkbox on the Budget Analyzer tab. If the MAT-files with digital maps are not available on the path, the following dialog box appears. Click the Download and Extract button to add the required map files to the MATLAB path.

Alternatively, you can download and unpack the MAT-files by entering this code at the MATLAB command prompt.

maps = exist('maps.mat','file');
p836 = exist('p836.mat','file');
p837 = exist('p837.mat','file');
p840 = exist('p840.mat','file');
matFiles = [maps p836 p837 p840];
if ~all(matFiles)
    if ~exist('ITURDigitalMaps.tar.gz','file')
        url = 'https://www.mathworks.com/supportfiles/spc/P618/ITURDigitalMaps.tar.gz';
        websave('ITURDigitalMaps.tar.gz',url);
        untar('ITURDigitalMaps.tar.gz');
    else
        untar('ITURDigitalMaps.tar.gz');
    end
    addpath(cd);
end

If you have an already customized link budget inputs/outputs, including availability will restore the link budget to its default inputs/outputs. A different dialog box opens up in this case where you can choose to either cancel or consent to the inclusion of ITU-R P.618 propagation losses for availability analysis.

This figure shows the updates to the configuration in the Link Budget (tags N6, N7, and N8) and Link (tag PL5) tabs, after the MAT-files are added to the MATLAB path.

In this app, Total atmospheric losses (tag N7) calculation with P.618 propagation model assumes the antenna type as parabolic.

Customize Inputs and Outputs

Customize the Properties and Results tabs in the Satellite Link Budget Analyzer app using the Customize Input/Output tab.

This example is applicable when you choose static link budget analyzer option at the app launch.

Open the Satellite Link Budget Analyzer app and select the Customize Input/Output tab.

On the Customize Input/Output tab:

• Use the options in the Add New Property section to add new properties.

• Use the options in the Add New Result section to add new results.

• Use the buttons in the Close section to accept or cancel the changes.

To delete a property or result, select it and click Delete in the respective section.

The default configuration in this example includes P.618 link availability analysis. To include ITU-R P.618 propagation losses for availability analysis, select the Include P.618 Losses checkbox on the Budget Analyzer tab.

Add Customized Properties and Results

Add customized properties and results by following these steps.

1. Add a new link property, FEC code rate. In the Add New Property section of the Customize Input/Output tab, select Link from the Type list. In the Unit box, type -. In the Default value box, type 0.5. Click Add Property. The Link Properties section of the Properties tab now includes FEC code rate (tag PLC1).

2. Add another link property, Coding gain. Select Link from the Type list. In the Unit box, type dB. In the Default value box, type 4.2. Click Add Property. The Link Properties section of the Properties tab now includes Coding gain (tag PLC2).

3. Add a new result, Required Eb/No with FEC. In the Add New Result section of the Customize Input/Output tab, type PL4 - PLC2 (Required Eb/No - Coding gain) in the Formula box. In the Unit box, type dB. Click Add Result. The Results tab now includes Required Eb/No with FEC (tag NC1).

4. Add another result, Margin with FEC. Type N12 - NC1 - PL7 (Received Eb/No - Required Eb/No with FEC - Implementation loss) in the Formula box. In the Unit box, type dB. Click Add Result. The Results tab now includes Margin with FEC (tag NC2). Note that this result considers FEC while calculating the margin, and is different from Margin (tag N13) which excludes FEC in its calculations.

5. In the Close section of the app toolstrip, accept all the changes.

This figure shows these updates in the Properties and Results tabs.

Delete Existing Results

Delete existing link analysis results by following these steps.

1. In the Results tab, select Rain attenuation (tag N6) and click Delete in this tab. Repeat this process for Total atmospheric losses (tag N7) and Total propagation losses (tag N8).

2. The formula for Received isotropic power (tag N9) on the Results tab is changed to use N5 instead of N8.

3. In the Close section of the app toolstrip, accept all the changes.

This figure shows these updates in the Results tab.

Create Custom Plots

Create custom 2-D line plots in the Satellite Link Budget Analyzer app for sensitivity analysis.

This example is applicable when you choose static link budget analyzer option at the app launch.

Add Custom 2-D Line Plots

Add customized 2-D line plots by following the steps in this example.

1. On the Budget Analyzer toolstrip, click the Add Plot button in the Plots section.

2. In the pop-up window, type Bit rate Vs Margin in the Name tab. Select Link in the X Type list and Bit rate (Mbps) in the X Axis list. Select Results in the Y Type list and Margin (dB) in the Y Axis list.

3. Click Add.

A new 2-D Line Plot tab opens up next to the Budget Analyzer toolstrip. This figure shows the new custom plot visible in the upper right corner of the app window, next to the default FSPL plot.

You can directly modify all the tabs (Name, X Type, X Axis, Y Type, Y Axis, and X range) that appear in the 2-D Line Plot contextual tab.

Add Custom 2-D Contour Plots

To add customized 2-D contour plots, follow the steps in this example.

1. On the Budget Analyzer toolstrip, in the Analyze section, click Select Links and select L1 and L2.

2. In the Plots section, click Add Plot.

3. In the Add Plot dialog, set type to 2-D Contour Plot.

4. Specify Name as Received Eb/No.

5. Set X Type to Transmitter and X Axis to Tx HPA power (dBW).

6. Set Y Type to Receiver and Y Axis to Rx feeder loss (dB).

7. Set Z Type to Results and Z Axis to Received Eb/No (dB).

8. Click Add.

A new 2-D Contour Plot tab for L2 appears next to the Budget Analyzer tab. This figure shows the new custom plots visible in the lower-right pane of the app window, next to the default Margin - L2 plot.

You can directly modify all the fields (Name, X Type, X Axis, Y Type, Y Axis, Z Type, Z Axis, X Range and Y Range) that appear in the 2-D Contour Plot tab. To access these fields for L1, in the lower-right pane, select the Received Eb/No - L1 tab.

Delete Custom Plots

To delete a custom plot, follow these steps.

1. Switch to the Budget Analyzer toolstrip.

2. On the toolstrip, click the Remove Plot button in the Plots section.

3. In the pop-up window, select the custom plot to delete and click Remove Plot.

Visibility Control for All Plots

To control the visibility of any default or custom plot, select the specific plot from the drop-down list present in the Plots section of the Budget Analyzer toolstrip.

By default, this app selects all plots and makes them visible. To hide any plot, clear it. Reselect it to make it visible again.

If you modify the app layout, you can click the Default Layout button on the Budget Analyzer toolstrip to return to the default layout.

Note that this app does not save the custom plots for a session.

Show Default Time-Varying Link Budget App Configuration

This example shows the default configuration that appears when you choose the time-varying link budget analyzer when launching the Satellite Link Budget Analyzer app. The figure shows the displayed results and visualizations, which analyze the default satellite communications link.

The upper-left pane of the app contains the Scenario Browser tab, which displays this default configuration:

• Ground Station 1, which has a transmitter: Transmitter 1

• Satellite 1, which has a receiver: Receiver 1

• Link L1, from source as Transmitter 1 and target as Receiver 1

The lower-left pane of the app contains the Ground Station, Link, and Satellite tabs. In the Ground Station and Satellite tabs, you can adjust the property settings for each entity in the configured link. To view or adjust the property settings of an entity, bring that entity into focus by selecting it in the Scenario Browser tab.

The top-right pane of the app window contains these plots:

• Satellite Scenario Viewer tab - A 3-D scenario visualization

• Margin tab - Link margin 2-D plot

The bottom-right pane of the app window contains the Link Budget tab, which shows the computed link budget results.

Configuration Including P.618 Link Availability Analysis

The app supports analyzing the time-varying satellite communications link availability through the propagation loss model defined in Recommendation ITU-R P.618. For details on the P.618 propagation loss model, see Earth-Space Propagation Losses.

To include ITU-R P.618 propagation losses for availability analysis, select the P.618 Losses checkbox in the Edit Scenario tab on the toolstrip. If the MAT-files with digital maps are not available on the path, a dialog box appears. Click the Download and Extract button in the dialog box to add the required map files to the MATLAB path.

After the MAT-files are added to the MATLAB path, you can notice these updates in the app once you click Analyze button on the toolstrip:

• A new Availability tag appears in the Link tab.

• In the Link Budget tab, two new columns, Rain Attenuation and Total Atmospheric Losses, are added in the table. Results in columns RIP, C/No, Eb/No, and Margin, are updated to include atmospheric losses.

Parameters

Static Link Budget

BUDGET ANALYZER — Static link budget configuration

tab

This figure shows the BUDGET ANALYZER tab with the factory default configuration.

Use the Ground Station, Link, and Satellite tabs to adjust property settings for the link budget entities shown in the Link Canvas tab.

Ground Station — Ground station location, transmitter, and receiver settings

tab

Select the Ground Station tab to set the location, transmitter, and receiver settings for the ground station highlighted in the Link Canvas tab. For information about customizing satellite, ground station, transmitter, receiver, and link properties, and the link budget result computations, see CUSTOMIZE INPUT/OUTPUT.

Satellite — Satellite location, transmitter, and receiver settings

tab

Select the Satellite tab to set the location, transmitter, and receiver settings for the satellite highlighted in the Link Canvas tab. For information about customizing satellite, ground station, transmitter, receiver, and link properties, and the link budget result computations, see CUSTOMIZE INPUT/OUTPUT.

Link — Link characteristics

tab

Select the Link tab to set link characteristics for the link highlighted in the Link Canvas tab. For information about customizing satellite, ground station, transmitter, receiver, and link properties, and the link budget result computations, see CUSTOMIZE INPUT/OUTPUT.

Customize Input/Output — Customize input properties and computations used for output

tab

To view or customize input properties and computations used for output, on the BUDGET ANALYZER tab, click Customize Input/Output to switch to the CUSTOMIZE INPUT/OUTPUT tab. In the CUSTOMIZE INPUT/OUTPUT tab, you can

• Change settings of the satellite, ground station, transmitter, receiver, and link properties from the factory default inputs

• Add and delete satellite, ground station, transmitter, receiver, and link input properties

• Add, delete, and modify formulas used to compute link budget output results

Plots — Visualization options

tab

View free-space path loss (FSPL) in 2-D line plots and link margins in 2-D contour plots that characterize the links. In addition, you can create custom 2-D line and 2-D contour plots. These custom plots appear next to the existing plots.

Export — Export link budget analysis

button

You can use the Export button to perform these options.

• Export to MATLAB script generates the equivalent MATLAB code for sensitivity analysis. You can modify the exported script to study the impact of link budget parameters on link performance.

• Export to PDF exports the link budget analysis to a PDF.

CUSTOMIZE INPUT/OUTPUT — Customize static link budget computations

tab

This figure shows the CUSTOMIZE INPUT/OUTPUT tab with the factory default configuration.

In the CUSTOMIZE INPUT/OUTPUT tab, you can

• Use the Properties tab to change settings of the satellite, ground station, transmitter, receiver, and link properties from the factory default inputs. You can also add and delete satellite, ground station, transmitter, receiver, and link input properties. On the Properties tab, you can use the Restore to factory button to load the factory default property configuration in the current app session.

• Use the Results tab to add, delete, and modify formulas used to compute link budget output results. On the Results tab, you can use the Restore to factory button to load the factory default results configuration in the current app session.

Time-Varying Link Budget

TIME-VARYING LINK BUDGET — Time-varying link budget configuration

tab

This figure shows the TIME-VARYING LINK BUDGET tab with the default configuration.

Use the Ground Station and Satellite tabs, in the lower-left pane of the app window, to adjust property settings for the respective link budget entities shown in the Scenario Browser tab.

Ground Station — Ground station location, and transmitter/receiver settings

tab

Select the Ground Station tab to set the location, and transmitter/receiver settings for the ground station highlighted in the Scenario Browser tab.

Use the Add or Delete button in Edit Scenario tab on the toolstrip to add or remove ground stations.

Satellite — Satellite orbital parameters, and transmitter/receiver settings

tab

Select the Satellite tab to set the orbital parameters, and transmitter/receiver settings for the satellite highlighted in the Scenario Browser tab.

Use the Add or Delete button in Edit Scenario tab on the toolstrip to add or remove satellites.

Link — Link characteristics

tab

Select the Link tab to view link characteristics for the link highlighted in the Scenario Browser tab.

Use the Create Links or Delete button in Edit Scenario tab on the toolstrip to create or remove links.

Edit Scenario — Modify components in scenario

tab

To modify the default or a custom scenario, use these buttons available in the Edit Scenario tab.

• Add — Add components, such as ground station, satellite, transmitter, or receiver, directly to the scenario.

  • When you add a satellite, a dialog box appears which enables you to add a satellite directly from a TLE file or by specifying its orbital elements. The same dialog box also enables you to create a default transmitter and a receiver by selecting the respective checkbox.

  • Similarly, when you add a ground station, the dialog box enables you to create a default transmitter and a receiver by selecting the respective checkbox.

  • When you add a transmitter or a receiver, by default, the app selects gaussianAntenna object from Satellite Communications Toolbox. However, you can choose an antenna object from Antenna Toolbox™ or Phased Array System Toolbox™.

• Create Links — Create link capability for the transmitters and receivers in the scenario.

• Delete — Delete the selected scenario component in the scenario browser.

• Clear Scenario — Clear the scenario browser and create an empty satellite scenario.

• P.618 Losses — Analyze link availability with P.618 propagation data and prediction methods, defined in Recommendation ITU-R P.618.

Import Scenario — Import custom scenario

button

You can use the Import Scenario button to analyze a custom scenario.

• Import scenario object from MAT file — Imports a satellitescenario from a MAT file.

• Import scenario object from workspace — Imports a satellitescenario directly from the MATLAB workspace.

For an example of how to model and import a custom satellite scenario, see Import Custom Scenario into Time-Varying Satellite Link Budget Analyzer.

Visualize — Visualization options

tab

These 2-D and 3-D visualizations options characterize the links.

• Satellite Scenario Viewer tab — Visualize a 3-D scenario showcasing the orbiting satellite, ground station, and link.

• Margin tab — View 2-D link margin plot.

Programmatic Use

satelliteLinkBudgetAnalyzer

satelliteLinkBudgetAnalyzer opens the Satellite Link Budget Analyzer app.

Version History

Introduced in R2021a