InSAR-IW or EW

Dear all,

  1. We have two modes, EW and IW. Are both interferometry?
  2. If we want to do interferometry, we must have phase information, something that we have in SLC data. Does it mean, we can not work with GRD mode for making interferograms and calculating displacements?
  3. I know we can calculate ice velocity with GRD products and we can calculate displacements by SLC products.
    I think SLC is interferometry not GRD. Am I right? Can we make interferogram with GRD products or not? How ice velocity (GRD) and ice displacement (SLC) can be related together? Can we get any result about ice or terrain displacement(SLC) with calculating ice velocity(GRD)?
    What is difference between EW-SLC and IW-SLC?
    Cheers,
    Marjan
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EW are the same as IW. They have 5 subswath instead of 3 for IW making EW extra wide. EW is mostly acquired in the Arctic and coastal areas to support ice and ship detection applications. See the Sentinel mission and user guides.

SLCs are the only type of products you can use for interferometry because they contain the phase information within the complex value data. GRDs are for working with only the backscatter for other applications.

If the ice moves a lot, you will have poor coherence and therefore you will get a poor interferogram from an SLC for measuring displacement.
With the GRDs and the offset tracking, you can measure fast movement such as glacier velocity.

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Hi lveci,

One question, with GRD I can measure fast movement such as dunes velocity???

Do you mean sand dunes?

Hi falahfakhri

Yes, sand dunes!

If the pattern stays pretty much the same the pattern-matching will work…worth a try.

Hi,

Actually I didnt apply this technique before, But from the initial technique point view, I think we could take some issues in our account,

The direction of the sands dunes, so in this case to use Ascending Or Descending Or both it means it doesnt matter,

the second issue is the backscatters of sands comparing to the glacial,

I think you could try taking Ascending pairs different time period, the same for descending and apply the same processing for GRD

All above is personal opinion -:slight_smile:

Thanks very much falahfakhri, your opinion and all opinions are very important for achieve an good analysis!!!