On the Issue of Short-Term Decorrelation in Forest Tomography with Companion SARS

In the framework of developments of 3D forest SAR Tomography (Tomo-SAR), the issue of extensive and detailed characterizations of temporal decorrelation phenomena has emerged, especially for the future spaceborne operations. However, investigation has not been covered by ESA campaigns of height-varying characteristics of decorrelation processes acting at the short-term (fractions of second) scale, for the common case of volumetric scatterers complexly moving in windblown forests.In this work, a methodology is reported for new analyses of 4D Differential Tomography type of forest temporal decorrelation phenomena, exploiting a ground-based miniradar array with very quick acquisition capabilities. Moreover, corresponding recent real data results are presented, developing characterizations of both height- and time-varying behaviours of the short-term decorrelation in a representative experiment for a stand of trees in Italy (PisaScat experiment), in two different wind conditions and seasons.Consequently, indications are obtained that short-term decorrelation processes can affect also advanced spaceborne Tomo-SAR systems based on tandem (i.e. formation-flying) configurations, depending on the satellite time-lag, and their related products.This still unprecedented characterization concept and the new findings can be useful for current Tomo-SAR and also Pol-InSAR analyses, and most importantly, for development of the advanced mission concepts and programs of SAOCOM-CS-like kind, including LuTan-1.