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Satellite Link Budget Analyzer

Analyze link budgets for satellite communications

Description

The Satellite Link Budget Analyzer app enables you to analyze link budgets for satellite communications.

Using the app, you can:

  • Analyze link budgets by specifying inputs properties related to

    • Location, transmitter, and receiver characteristics for satellites and ground stations

    • Atmospheric conditions for links

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

  • Have insight into intermediate link budget computations

  • Calculate, compare, and visualize results across a sweep of multiple parametrized design constraints

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

Default satellite link budget app session window, showing the budget analyzer tab

Open the Satellite Link Budget Analyzer App

MATLAB® Toolstrip: On the Apps tab, under Signal Processing and Communications, click the app icon. Satellite Link Budget Analyzer button

MATLAB Command Prompt: Enter satelliteLinkBudgetAnalyzer.

Examples

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This example shows the default configuration that appears when you open the Satellite Link Budget Analyzer app.

Default Configuration Without Link Availability Analysis

A message dialog box opens before the app launches. To analyze the link budget with the P.618 scenario, you must download, extract, and add the MAT-files with digital maps on the MATLAB path. Follow the instructions in the dialog box.

If you do not wish to use P.618 calculations in the link budget, close the dialog box to launch the app.

The figure shows the displayed results and plots, which analyze the default satellite communications link.

In absence of the digital maps, the tags (N6 and N7) are empty. In this case, the values in tag N8 (Total propagation losses) are equal to the values in tag N5 (FSPL).

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 property settings for each entity in the configured links. To view or adjust the properties 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).

Default Configuration with Link Availability Analysis

The app supports analyzing the satellite communications link availability through the propagation loss model defined in Recommendation ITU-R P.618-13. For details on the P.618 propagation loss model, see Earth-Space Propagation Losses.

If the MAT-files with digital maps are not available on the path, download and unpack the MAT-files by entering this code at the MATLAB command prompt.

Alternatively, you can download and unpack the ITURDigitalMaps.tar.gz file to a directory that is on the MATLAB path.

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

This figure shows the updates to the configuration in the Link Budget (tags N6, N7, and N8) and Link (tag PL5) tabs.

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

Open the Satellite Link Budget Analyzer app. These figures show the default configuration on the Budget Analyzer and Customize Input/Output tabs.

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.

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. The formula for Margin (tag N13) on the Results tab is changed to use NC1 instead of PL4.

  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.

Parameters

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

Default satellite link budget app session window, showing the budget analyzer tab

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

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.

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.

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

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

Default satellite link budget app session window, showing the customize input/output tab

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.

Programmatic Use

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satelliteLinkBudgetAnalyzer opens the Satellite Link Budget Analyzer app.

Introduced in R2021a