Sentinel-1 Processing Steps?

ak.h · March 8, 2019, 10:41am

Hello,

can anyone tell me which pre-processing steps are applied on the Sentinel-1 products?

As they are provided in gamma nought, at least calibration must be involved. In the documentation I saw that thermal noise is removed as well (https://sentinel-hub.com/develop/documentation/eo_products/Sentinel1EOproducts). What else? In which order? With which parameters?

I’m trying to figure out if the Sentinel Hub can save me my processing routine or at least parts of it…

Thanks

marko.repse · March 8, 2019, 1:46pm

Hi,
Correct, calibration and thermal noise reduction are applied. This is done first and at the same time. After that the geolocation processing follows, either orthorectified or non-orthorectified, depending on you settings.
Note that as of this writing speckle filtering and terrain flattening are not supported.
I hope this helps

ak.h · March 22, 2019, 1:02pm

Thank you for the response!
I have some follow up questions:

Is some kind of resempling or coregistration involved?
Will terrain flattening be supported in the future or why wasn’t it included yet?
During orthorectification - what kind of DEM is used?
Are the original orbit state vectores used or is the updated orbit file applied? Why so? Is this relevant for this processing chain anyway?

Thanks

gmilcinski · March 22, 2019, 7:54pm

I can respond to some of these. @marko.repse can probably answer to the rest.
-there is no coregistration involved
-there is averaging involved on lower scales. If you use it on natural scale, there is no resampling.
-there is no terrain flattening and there are no mid-term plans to do it
-we use MapZen’s DEM (https://registry.opendata.aws/terrain-tiles/)

marko.repse · March 25, 2019, 9:52am

We use the original orbit state vectors as they are sufficient for GRD use. Of course this only applies to orthorectified imagery; for non-orthorectified they are not needed.

buwuyou · May 15, 2019, 10:50am

Hi,
Is the sigma0 calibrated Sentinel-1 data available from sentinelhub wms service?

gmilcinski · May 15, 2019, 10:29pm

We currently support only gamma0.

marko.repse · June 6, 2019, 7:26am

Actually you can get sigma0, you can set this in the layer settings in your dashboard (https://apps.sentinel-hub.com/dashboard/#/configurations)

buwuyou · June 6, 2019, 11:43am

It is great! And thanks for the update! I actually saw it yesterday and wondered whether it’s implemented.

rit · May 5, 2020, 5:41am

@gmilcinski, is there a page or paper documenting the pre-processing steps that are done on SentinelHub for Sentinel-1 data? This page https://www.sentinel-hub.com/develop/documentation/eo_products/Sentinel1EOproducts is not comprehensive regarding the pre-processing done.

I would like to cite that resource in papers written using SentinelHub. I would like to make a version of Figure 1 here: https://www.mdpi.com/2504-3900/18/1/11 and basically be able to say that Sentinelhub does all or some of the processing steps listed there. thanks!

gmilcinski · May 5, 2020, 5:55am

There is another description here:
https://docs.sentinel-hub.com/api/latest/#/data/Sentinel-1-GRD

We do not have anything more detailed, sorry about that.

palaiya · May 15, 2021, 11:02am

@gmilcinski @marko.repse I have downloaded the sentinel-1 GRD data for my AOI using the this .
I see the pixel size of the downloaded image in QGIS is 8.913742424687676191e-05,-6.860746012812835026e-05.

Where as when we download the GRD data separately and perform following steps :

we get pixel size of 10 -10 because of range doppler terrain correction step. So, is there any way by means of which we can perform this step and get the processed result?