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 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.

• Gain insight into intermediate link budget computations.

• Calculate, compare, and visualize results 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 Satellite Link Budget App Configuration

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

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.618-13. 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.

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.

Create Custom Plots

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

Add Custom 2-D Line Plots

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

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

• 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.

• 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.

Delete Custom Plots

Delete the custom plot by following these steps.

• Switch to the Budget Analyzer toolstrip.

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

• 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, all plots are selected and 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 custom plots are not saved for a session.

Parameters

BUDGET ANALYZER — 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

CUSTOMIZE INPUT/OUTPUT — Customize 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.

Programmatic Use

satelliteLinkBudgetAnalyzer

satelliteLinkBudgetAnalyzer opens the Satellite Link Budget Analyzer app.

Version History

Introduced in R2021a