About InSAR atmospheric effects

[falahfakhri]

Dear Colleague,

Please find below a few links within step forum are related to Sentinel 1, and DEM generation, more other you can find answer your queries as well,

Phase to elevation - BLACK product

Let’s discuss the matter one by one, First point I mentioned in here the selecting SAR pairs conditions for DEM creation In case we try up to apply all the aforementioned conditions to your case, or Sentinel -1 case, we could find that, more than one of S1 characteristics don’t meet the DEM creation, and example of that is, the temporal baseline, as you know, there’s no tandem pass in S1, also the perpendicular baseline is important to take in account as it is mentioned, Here our colleague @A…

DEM Interferometry with SLC

Did you take a look at this whole topic of DEM generation? Also this one ?

Sentinel-1 A- extracted DEM

In general S-1 is not recommended for DEM creation ,But in case S-1 is the only available solution, please put in mind the points are mentioned in the following post, Selecting Images for InSAR DEM generation, Source of the post It’s incomparable between S-1 created DEM and SRTM1 for the reasons are mentioned in the following post, Incomparable DEM resulted from S-1 pair and SRTM, Source of the post

DEM generation

Might be this helpful https://www.ims.tuwien.ac.at/publications/tuw-138083.pdf

DSM from Sentinel-1

What is your question? There are a lot of topics in here dealing with this challenge:

Coming back to your demands,

@sentinel

always share a date (T1-T2, T2-T3, T3-T4). Why is that? What would be the effect of having a disconnected timeline (T1-T2, T3-T4)

In general and far a way from whether S1, is the best solution for DEM creation Or not!; basically creating DEM means to get an absolute elevation of the bare earth for a specific area, I’m not talking now about the difference between DTM, and DSM, and DEM,

For getting good result of the absolute elevation Tandem is the best for so, however Tandem is not available via S1, therefore less time expansion in case of S1 is the best in order to avoid any unwanted ground movement, of course it also depends on the study area whether has been subjected to any natural or an anthropogenic effect or not corresponding to time expansion between the two S1 acquisitions, that’s why the average connecting time might be is the best solution in this case in order to decrease the DEM quality error.

@sentinel

The temporal baseline between acquisitions is identical, but what it the time span between interferometric pairs is not the same.

Let’s take this example, T = S1 image Ok,

T1 - T2 = Interferogram1,

T2 - T3 = Interferogram2,

So the time interval of the first infgm1. let’s suppose 6 days, and the infgm2 is also 6 days, ultimately the interval time between the both infgms, is only 6 days,

@sentinel

Checking the post, can you confirm the order of steps. I see you discussed first the option of averaging the intf BEFORE unwrapping but did not work out. Can you elaborate on this? The alternative is then to stack the unwrapped phases and then proceed with DEM generation?

From your question here, I think it’s recommended for you to get back to the principles of SAR, and InSAR, order to get the basic experience of processing steps,

I hope you can use the step forum search to find out all the answers I’m sure already exists fulfill all your queries and demands.