I have been working through the ASF's "Recipes" for the creation of a DSM from Sentinel 1 (A and B) imagery.
I am able to produce a DSM, and am relatively happy with the results in terms of the surface produced - it appears to follow the trends of my known datasets (hills where there should be hills and valleys where there are valleys).
I have however noticed artifacts or static in some areas of the surface produced. Please see the image below showing what I mean - basically areas of spikes and troughs in random places on the surface. These areas tend to be consitent amongst different periods too (for example I produced a 2018 surface and the same issues appeared in my 2016 surface).
The image above shows an example of a cross section through an area. As can be seen, the elevation drops from around 300m to less than 100 and then back up to 400m. All within around 400m in the horizontal.
At moment I have been using the default values in the ESA SNAP Toolsets. My question I guess can be broken into two parts. 1) What created this "static" in the image - is it topography (large hills creating interference) or a setting / value in SNAP I should be tweaking? 2) If it is a setting, what should I be looking at? The process of generating the DSM is a long one, and having to repeat each step is time consuming, so a general idea of where I should focus my attention would help.