"Creating LEO Constellations with Skydel" Tutorial Questions

Regarding the Creating LEO Constellations with Skydel tutorial, there are a few steps that are not very clear for me.
At the part 1.3.3.b Leo Sat signal definition. Instructions say to “In the window that appears, select the path of the IQ file to be generated.” But we are not generating new files here right? I think I should add the IQ files that were generated in 1.2. Generate IQ signal step, which were modified to have a center frequency of 2 GHz. I did so, but I got a “Center Frequency mismatch error”.

Also, there is a screenshot that shows the pseudorange of the receiver. Where is that screenshot from? Is it skydel or another program? (By the way, I have ublox8 receiver.)

Hi @mohdyaser,

  • There is an error on the site, but this part consists of loading the IQ file which has already been generated in the document section (1.2. Generate the IQ signal) and which will be used as the signal emitted by your LEO satellite. So yes, no new IQ file is generated in this part.

  • Indeed, the center frequency of 2 GHz is the frequency at which the LEO signal will be transmitted by the LEO satellite. As we are using the jamming tool to configure the LEO constellation, we also need to change the center frequency of the interference output to 2 GHz in Settings → Output → Signal selection edition:

After this change, you should no longer get this error.

  • The screenshoot is from the Ublox Receiver UI which you can download here: u-center. We used version 20.10 for this example.



Thanks a lot Grace, I will test it today and see how things go.

@Grace I indeed solved the central frequency error and the simulation works now, but the interference (Leo signals generated by IQ files) are not showing (check the screenshot). Why is that? How can I solve the issue?


Edit: Any other predefined signal (chirp, pulse, etc.) works normally.

Hi @mohdyaser,

I apologize for the delay!
Thanks for the screenshot, it helps. Everything seems normal to me, there is no warning.
The signals seem to be present but they are not visible. I think the IQ signals may be too weak, so I will advise you to increase the IQ signal power.

I did a quick test and I can see the IQ signal spectrum: