Basics of microwave radar & SAR polarimetry and its applications

The development of radar polarimetry and radar interferometry is advancing rapidly, and these novel radar technologies are revamping "synthetic aperture radar imaging" decisively. In this exposition the successive advancements are sketched; beginning with the fundamental formulations and high-lighting the salient points of these diverse remote sensing techniques. Whereas with radar polarimetry the textural fine-structure, target-orientation and shape, symmetries and material constituents can be recovered with considerable improvements above that of standard \´amplitude-only polarization radar\´; with radar interferometry the spatial (in depth) structure can be explored. In \´polarimetric-interferometric synthetic aperture radar (POL-IN-SAR) imaging\´ it is possible to recover such co-registered textural plus spatial properties simultaneously. This includes the extraction of \´digital elevation maps (DEM)\´\´ from either \´fully polarimetric (scattering matrix)\´ or interferometric (dual antenna) SAR image data takes\´ with the additional benefit of obtaining co-registered threedimensional \´POL-IN-DEM\´ information. Extra-wide-band POL-IN-SAR imaging - when applied to \´repeat-pass image overlay interferometry\´ - provides differential background validation and measurement, stress assessment, and environmental stress-change monitoring capabilities with hitherto unattained accuracy, which are essential tools for improved global biomass estimation. More recently, by applying multiple parallel repeat-pass EWB-POL-D(RP)- IN-SAR imaging along stacked (altitudinal) or displaced (horizontal) flight-lines will result in \´tomographic (multi-interferometric) polarimetric SAR stereo- imaging\´, including foliage and ground penetrating capabilities. It is shown that the accelerated advancement of these modern \´EWB-POL-D(RP)-IN- SAR\´ imaging techniques is of direct relevance and of paramount priority to wide-area dynamic homeland security surveillance and local-to-global envi- - ronmental groundtruth measurement and validation, stress assessment, and stress-change monitoring of the terrestrial and planetary covers.