Hi to all of you!
I am working with coherence maps over agricultural zone in Argentina, for crop classification.
I carried out two coherence maps, but one of this have a low coherence. Both are six (6 days) temporal baseline. Considering that spatial and temporal baseline are short, why second coherence maps have low coherence?? Can I help me?
I see two hypothesis:
MAST and SLV Coregistration problems.
Original SAR Data problems
Have someone similar problem?
Thanks’ a lots.
Hi ABraun! Thank you for your response.
- We have removed topographic phase for all maps.
- We found low coherence in full image for the map (coh_IW3_VV_23Apr2020_29Apr2020). But the same does not happen with:
Problem occur between 23Apr2020 and 29Apr2020. For example:
We consider that when the ground remains bare between both dates, coherence should see high. We investigate the Mission Status (https://sentinel.esa.int/web/sentinel/missions/sentinel-1/mission-status) for this dates, but it is all ok.
Our hypothesis are orbital error or bad focalization in acquisition 29Apr2020. Because the behavior is the same in the three swaths (IW1, IW2 and IW3). For this reason we discard possible heavy rain or weather effects.
Are you agree? Thanks a lots
have you tried how the coherence looks without the orbit files applied. Sometimes errors are introduced if orbit data is (very rarely) of faulty quality.