Request for tutorial : Atmospheric / Ionospheric correction

Dear users and developers,

SNAP 9 has introduced a very promising feature that corrects the effect of ionosphere, mostly due to the total electron content change between SAR pairs. The technique is based on state-of-the-art procedures, using the splitband technique.

This is a HUGE feature that is super important in slow-moving areas, where this component is the same order of magnitude as the displacement we want to measure. For that, I’d like to thank the SNAP development team.

This being said, I see an increasing number of users that are asking me (or via the official forum) how to use it. As I’m currently speaking, this functionality is not present in tutorials. If I’m wrong, please redirect me to the document.

It would be really nice to have a structured protocol on how to use / parametrize the module, and where to use it in a standard Interferometric protocol. If that’s possible, can a tutorial on subject be added to a “wish list” somehow? Or at least an answer here in Common Workflow Language

Best regards,



Thank you for your request Quentin, I agree that such a tutorial is definitely needed.

Hello all

I was wondering what the input of the Ionospheric correction is. Is that 3 unw.Ifgs (unwrapped ifgs) from the same frame? I tried that and also tried three frames below each other, but did not work and I got two errors. please see below:

  • The input products should have the same size
  • The input products should have different center frequencies

Any idea how to solve it?


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Hello everyone!

I try to do Ionospheric correction for Sentinel-1 data. But it doesn’t work. I have a such error:
“The input products should have differen center frequencies”.
What does it mean?

I have completed 3 interferograms for my area of interest

I have done preproccessing (img) and phase unwarping.

did you find the solution of this problem “The input products should have different center frequencie”?

Not yet :slight_smile:

I experimented with ionosphere correction for ALOS2 data and made the following observations:
• Release 9.0.4 produces distinctly different outcomes than release 9.0.3.
• Release 9.0.4 confounds “wrappedIonosphericPhase” and “wrappedCorrectedPhase”, that is the bands are named wrongly.
Why are the results of the two releases different? Could you please fix the bug with the naming and tell me if the bands in 9.0.4 are only named wrongly or if they are calculated wrongly?

I made further experiments and it seems that there is no problem regarding how the bands are calculated. Only the names are wrong.

@djagula can you check this?

A JIRA ticket ([SNAP-3590] - JIRA) has been created to track the problem. We will look into it. Thank you.