Introduction

This technical note explains how to create and define a new constellation in Skydel. Related to this, it will explain how to create a custom signal and allocate it to the right constellation.

This technical note will not focus on the building and compilation of the custom signals. To have more information about this, there is a specific documentation online: Custom Signal | Skydel Plug-ins Documentation. This note will give more specifications on how to use and parametrize a new constellation or a signal in Skydel.

In Skydel, a custom constellation is available if the license is activated. However, no specification has been given to this constellation. That is why it is not visible in the outputs of Skydel, only the default constellations are displayed.

To make a new custom constellation available, two components need to be defined:

  1. The constellation itself (name, number of satellites, trajectories, …)
  2. The signals broadcasted by the constellation.

1. New Constellation

In the Settings of Skydel, there is a specific menu named “CUSTOM”. This is where the constellation will be defined.

Before going into this menu, you will define the characteristics for the new constellation. In Edit > Preferences go to Custom Constellation and choose the name of the constellation as well as the number of satellites.

To apply the changes, Skydel will need to be restarted. Now, your new constellation is displayed with configured name in the Settings of Skydel.

In this custom constellation menu, you will find the same menus as in any other constellation menus (GPS, GALILEO, …). To define the position of the satellites at the time of the simulation, a Rinex file must be given to Skydel for the extrapolation of the trajectories. In General > RINEX file, import the ephemeris of the satellites.

Each PRN included in the RINEX file will enable a custom satellite in Skydel. You can find the list of all enabled satellites in CUSTOM/ Signal Enable/Disable.

Once done, your new constellation has been set. You can also set the other menus to best fit the constellation behavior. For example, you can import the pattern of the broadcasting antennas of the satellites.

Warning: you can encounter some errors when importing the Rinex file. Be careful to the format and indentations inside the file.

2. New Signals

Now, your constellation has been created but no signal is broadcasted.

To create your custom signal, you can follow this tutorial: Custom Signal | Skydel Plug-ins Documentation.

Once your custom signal has been compiled as a plug-in and its corresponding XML file is defined, it is ready to be imported into Skydel. To do so, simply place the compiled plug-in and its associated XML file in the plug-in discovery folder, located at Skydel-SDX / Plug-ins.

If you’re using a custom signal example that relies on a downlink file, make sure to also copy the required downlink file into the same folder, alongside the plug-in and XML file.

It’s important that the custom signal plug-in and the XML file have the same name. For example, if the plug-in is named custom_custom_ca.dll (on Windows) or libcustom_custom_ca.so (on Ubuntu), the XML file should be named custom_custom_ca.xml.

After restarting Skydel, you can enable your custom signal plug-in like any other plug-in via the Help / Plug-ins… menu. The following screen must be displayed.

Enable the plugin by clicking on the Enable button and close the Plug-ins panel.

Once enabled, your custom signal will appear in the Settings / Custom Signals / Your Custom Signal Name page, where you’ll have access to its basic configuration options. It will also be available for assignment to an output. 

Custom Signal constellation attachment setting is included in the Custom Signal XML file.

  • If the new signal is broadcasted by an existing constellation, it will be displayed in the Constellation section (e.g. surrounded in green)
  • If the signal is broadcasted by a new Custom constellation, a new constellation will appear in the output with the signal (e.g. surrounded in red)

That’s it, you’re now ready to run simulations using your custom signal! You can activate the signal to simulate it.

Conclusion

This document gives a quick overview of the way to configure a new custom constellation with its associated custom Signal.

A custom constellation needs a custom signal, but the reverse is not true. A custom signal can be allocated to an already existing constellation.

Ref – SCD-000262-REV1