Lack of triangularity in SAR interferometric phases

Inhalt:
If three SAR images are available, it is possible to form three interferograms. In some cases the phases of the three averaged interferograms will not agree among each other and indicate a sort of phase excess or deficit (which we call "lack of triangularity"). In this paper we illustrate theoretically which models can explain such phenomenon and show some real-data examples. The observation of lack of triangularity might be useful to derive informations on the target and also as a warning that the scatterer presents a temporal covariance matrix which is not intrinsically real.