S1 TOPS (ESD) Coregistration

Microwave Toolbox
1

Hi,

I downloaded the following two Sentinel-1A products:

  1. S1A_IW_SLC__1SDV_20160101T045559_20160101T045636_009296_00D6CE_50AA.zip
  2. S1A_IW_SLC__1SDV_20160113T045559_20160113T045636_009471_00DBD1_5884.zip

By selecting VV polarization and IW1 subswath I have applied the following interferometric processing:

  • S-1 TOPS Coregistration (TOPSAR Split, Apply orbit file, Back-Geocoding);
  • Interferogram Formation;
  • S-1 TOPS Deburst;
  • Topographic Phase Removal;
  • Multilooking.

And I got these results for coherence and interferometric phase (I only used matlab to generate the maps):

ori.png1088×840 394 KB

As we can see, there are some strange artifacts in interferometric phase which are clearly correlated with the bursts borders.

So in an attempt to mitigate these artifacts I repeated the processing but I used the “S-1 Enhanced Spectral Diversity” after the Coregistration step in the interferometric processing listed above. The results were even worse:

enh.png1059×842 389 KB

My question is: Is this the right approach to deal with this problem? If it is, am I doing something wrong? Why am I getting so bad results?

Thanks in advance.

PS: I’m using the precise orbits and the ASTER DEM.

2

Which version of the software are you using? There was a recent module
update 3.0.4 which addressed phase jumps from products processed in
2016. Go to Tools -> Plugins and check for updates.

3

I’m using the latest version, for when I click in “Check for Updates” I get a message saying: Your application is up to date!

SNAP Desktop implementation version: 3.0.4
SNAP Engine implementation version: 3.0.4
S1TBX version: 3.0.3

ver.png903×519 298 KB

I don’t know if it is important but I have been using snap through python scripts (snappy).

4

I have processed two other images over the same location and I got similar artifacts, though they are dimmer.

This problem raised me some doubts about whether I have chosen the right approach.

Is the “S-1 Enhanced Spectral Diversity” intended to overcome this kind of errors? (When I click the help button nothing happens)

If it is, have I applied rightly?
That is, after the S-1 TOPS Coregistration and before the Interferogram Formation?

Thanks.

5

Were you using restituted or precise orbits?

6

I am using precise orbits.

7

Hello.

I am farly new with dealing with SAR data, I have a methodology where I know that I need to do first some coregistarion and resampling of my images. I want to perform coherence and intensity correlation analysis.
I got 3 image.

  1. S1A_IW_SLC__1SDV_20160815T170526_20160815T170554_012614_013C81_7613.zip
  2. S1A_IW_SLC__1SDV_20160822T165740_20160822T165807_012716_013FF7_02A2.zip
  3. S1A_IW_SLC__1SDV_20160827T170542_20160827T170609_012789_014270_B9C6.zip

All of my images cover the AOI that I want. They are all ASCENDING and have VH-VV polarization. Which i believe is important for what i want do to. The thing is, that they cover the same AOI, but they are not the same track, meaning like they are from different positions.

This means that for example the sub-swath of one image lets say IW1, matches with the sub-swath IW3 of another image, but only partially or some times not even. What do you recommend to do in this case?

I was thinkign about extractin the area of interest first from the images, but dont know how to create a single of image of all the sub-swaths and then subset my area.

Thank you

8

Please ignore my last msg. I have figured out how my images need to be acquiered. Thank you so much!

9

Hello @juanesburgo:

Your work (appart) from the artifacts that you are getting, is very nicely done. I need to do coherence correlation analysis and was wondering if you could share with me some of your methodology to get the coherence and interferometry images.

I am starting with the co-registration, I have 2 images and I would like to know which are the best paramenters for the DEM co-registration, and resampling. Which method should I use and I also dont have a DEM of the area so would like to use a DEM avaiable in the software.

However, I do not understan where can I check if my co-registration was successful or accurate? As you can see I am relally new at all this SAR data and would really appreciate your help.

Thank you,
Daniela

10

Hello,

After doing ESD Coregistration, can someone explain me please, how to interpret the results of the co-registration, to say it was good or bad?

Kind Regards,
Daniela Palacios

11

Hi
I have problem about coregisteration of sentinel1 tops 2016 data
when I want to coregister the image S1 TBX says that" can’t download precise orbit file . you should download it and placed in a folder " I do it correctly but it doesn’t work!!
what should I do?

12

where did you download the orbit files manually and where did you place them?

13

the software itself said that download orbit file from https://qc.sentinel1.eo.esa.int/ and placed it to C:\AuxData\Orbits\Sentinel-1\POEORB\2016

14

for the newer versions of SNAP the location of the aux folder has changed:
have a look if this folder exists

C:\Users\yourname\.snap\auxdata\Orbits\Sentinel-1\POEORB\2016

15

unfortunately I don’t have this address!

Pasted image1920×1080 92 KB

16

create it then and place the zip files of the orbits in it (as long as 2016 is the right year)

You could also try to apply an orbit file to another image so the folder is created automatically by SNAP.

17

Thanks for your guide but it doesn’t work for me!

Pasted image732×929 120 KB

18

Hello
In auxdata folder create this root:
Orbits\Sentinel-1\POEORB\2016
if image acquisition date is different, change 2016 to appropriate year.
Then paste the orbit file (with .EOF or .zip extension) in created root.

19

Thank you Javad
I do it but it doesn’t work
I had S1TBX version 1.1.1 and update it to version 5 and this problem solve

20

Hi
do you know how we can choose the best polynomial degree for apply orbit file?