ABraun
April 8, 2017, 5:42am
4
technically yes. But the repeat cycles are usually quite long (24 days) which leads to temporal decorrelation, especially due to the wavelength of the c-band:
Atmospheric phase cannot be removed by a SNAP module as it cannot be modeled, like flat earth phase or topographic phase, for example. If you would make reference measurements of water vapor or have dense time-series data (example ) you could theoretically remove the atmospherical phase distortions. This is advanced however (example 2 ).
You calculate an interferogram between a pair of images. It shows you the differences between both images regarding their single phase signal. As the satelli…
thank you, @heinzollerketchup .
Generally, the longer the temporal baseline (=the time between two images) the higher is the decorrelation which leads to small coherence values. It also depends on the cover of the analyzed surface. Bare ground mostly shows slower decorrelation than one with high vegetation cover.
As you can see here (tested with S1 data), coherence decreases from 0.7 to nearly 0.1 within 6 12-day-cycles (12, 24, 36, 48, 60 and 72 days, blue to red)
[image]
Source: http://ieee…