Recent Advances in Radar Polarimetry and Polarimetric Sar Interferometry

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 three-dimensional ‘POL-IN-DEM’ information. Extra-WideBand 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 (MultiInterferometric) 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 environmental ground-truth measurement and validation, stress assessment, and stress-change monitoring of the terrestrial and planetary covers. In addition, various closely related topics of (i) acquiring additional and protecting existing spectral windows of the “Natural Electromagnetic Spectrum (NES)” pertinent to Remote Sensing; (ii) mitigating against common “Radio Frequency Interference (RFI)” and intentional “Directive Jamming of Airborne & Space borne POL-IN-SAR Imaging Platforms” are appraised. Synopsis: Radar Polarimetry is a rather difficult and complex multi-disciplinary subject, and it is mired by the fact that the IEEE Standards on Antenna Measurements [104] contain an ill-conceived, if not incorrect definition for the formulation of the polarization descriptors [127, 154]. Many radar engineers try to hold on at times not aware of the dilemma and more often for not finding a better and correct formulation [24]. Therefore, it was found necessary to expend considerably more efforts on re-assessing the foundations of radar polarimetry, resulting in the finding that there exist several new books, which are using plainly incorrect alternative formulations, which add to the misery. On top of it, there exist five rather different conceptual approaches to radar and optical polarimetry: (1) the standard Polarization Vector formulation [4], preferred by most radar engineers as followed in Mott [174] and Yang [299, 300]; (2) an algebraic Directive Jones Vector approach, first introduced by Graves [92] and further developed by Lüneburg [153], providing a considerable improvement over the standard method; (3) a Group-theoretic Polarization vector Approach, developed by Pottier [196]; (4) a Spinorial Approach initiated in quantum-optical analyses, which is more general [170] but not yet fully developed for radar polarimetry as persued by Bebbington [7]; and, (5) a Quaternion Approach persued in ellipsometry by Pellat-Finet [138, 139], which is currently being extended by Czyz [55] to radar polarimetry with the aid of the Inversion Point method, derived first by Kennaugh [116, 117] for the Poincaré polarization sphere [194]. Of specific relevance to the latter two approaches is the Clifford Cl (3) algebra which is based on a covariant formulation of electrodynamics in terms of paravectors in the Pauli algebra [6]. All of these closely interrelated and some mixed descriptions are being further Report Documentation Page Form Approved