Systematic Issues in Sentinel-1 RTC Products

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mmirzadeh
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Systematic Issues in Sentinel-1 RTC Products

by mmirzadeh » Thu Feb 09, 2023 6:06 am America/New_York

Hi all,

Recently, I ordered the RTC products of the HyP3 service over my study site from both Sentinel-1 SLC and GRD datasets on all amplitude, decibel, and power scales. When I checked the "JPG" files, I found several issues in some products. You can take a look at them in the attachment.
Do you think these issues are associated with the acquisition style of Sentinel-1 or any surface noises? Or the RTC progress could result in these issues! I believe these issues will affect any spatiotemporal analysis we want to use for the "Gamma0" or "Sigma0" SAR radiometry on any scale. So, I would appreciate your comments on fixing these issues in my research.

Sincerely,
Sayyed
Attachments
S1A_IW_20171030T022149_DVP_RTC30_G_gpufed_C5AA_rgb.jpg
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S1A_IW_20190930T142633_DVP_RTC30_G_gpufed_5376_rgb.jpg
S1A_IW_20190930T142633_DVP_RTC30_G_gpufed_5376_rgb.jpg (94.77 KiB) Not viewed yet
S1A_IW_20200128T142630_DVP_RTC30_G_gpufed_A964_rgb.jpg
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ASF - hjkristenson
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Re: Systematic Issues in Sentinel-1 RTC Products

by ASF - hjkristenson » Mon Feb 13, 2023 4:42 pm America/New_York

These signatures are indicative of Radio Frequency Interference (RFI).
This is a common problem in SAR acquisitions, and often occurs near airports or other installations that emit strong radio/radar signals. The acquisition data itself is impacted; it's not an issue introduced during RTC.

Unfortunately, it looks like most acquisitions over the ascending footprint you posted are impacted by RFI. You might have better luck with the descending acquisitions; some of them are also impacted, but not as many.

Try this search for the descending scenes over the same area:
https://search.asf.alaska.edu/#/?start=2017-01-01T09:00:00Z&end=2020-12-02T08:59:59Z&maxResults=1000&resultsLoaded=true&flightDirs=Descending&beamModes=IW&zoom=7.008&center=55.258,29.028&productTypes=GRD_HD,SLC&path=64-64&frame=488-488

There are a number of papers in the literature presenting methods for mitigation, but it's a difficult issue to solve. This paper has a good summary of the problem: https://www.ursi.org/proceedings/procGA17/papers/Paper_EFGHJ1-4(2957).pdf

mmirzadeh
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Joined: Fri Sep 23, 2022 8:49 am America/New_York
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Re: Systematic Issues in Sentinel-1 RTC Products

by mmirzadeh » Mon Feb 13, 2023 8:43 pm America/New_York

Hi,

Thank you so much for your message. It would be beneficial.
Since I am using the SAR Radiometry (Gamma0) in all amplitude, decibel, and power scales for a spatiotemporal analysis using machine learning algorithms, this issue creates an issue in the results. Still, I am thinking about how I can handle it.

Interestingly, as you said, the power network and stations may induct this issue in the SAR acquisitions, but I am not sure.

Sincerely,
Sayyed

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