I understand that the result of InSAR interferometry yields a LoS deformation and if deformation in the vertical or horizontal is to be computed, it should require additional gps observations at the site.
My first question is, could I simply solve for the components (vertical and horizontal) using geometry from the incidence angle?
Secondly, for DEM generated by repeat pass SAR images, i understand that the height obtain is relative. Can someone explain to me what does relative mean? Does it refer to the change in height from the first image to that of the second image? How then can I get an absolute height?