| Popis: |
Certain applications require topographic surveys below the vegetation cover. The use of radars with long wavelengths, such as L- and P-band, allows signal penetration through the forest volumetric structure. However, the interferometric phase center, resulting from this interaction, may be closer to or farther from the ground depending on the baseline and polarizations used. Recently, improvements in polarimetric synthetic aperture radar interferometry with the random volume over ground model have allowed the generation of terrain models with considerably increased accuracy. This work aims first at providing a theoretical background to support the comprehension of terrain model generation from the polarimetric and non-polarimetric SAR interferometry in regions with a dense vegetation cover. P-band data are provided by Bradar Indústria S/A. An analysis of the polarimetric model with full-polarimetric data is carried out. The analysis indicates the possibility of a robust terrain height estimation using only two polarizations, HH and HV. The dual-polarimetric method is then tested and compared with the non-polarimetric method. To evaluate the influence of the baseline on the estimations, short (20m) to very long baselines (145m) are used, to a flight height of 3.3km. Other contributions, such as the study of the influence of the horizontally and vertically polarized antennas phase center difference, as well as a variation of the spectral-based fine co-registration method with a phase offset calibration are presented. |
