Research On Data Processing Of P-band Fully Polarimetric SAR

P band polarimetric/polarimetric interferometric SAR system has important application values in terrain topology, forest tree height estimation and target classification and so on for its characters of long wave length/low frequency. However, the adjoint data characters of wide azimuth beam width, high ground to volume ratio and significant ionospheric turbulence have also brought new requirements and technical challenges for P band fully polarimetric data processing.With the IECAS (Institute of Electronics, Chinese Academy of Sciences) P band airborne fully polarimetric SAR system, this thesis focuses on the P band fully polarimetric SAR data processing, such as the wide azimuth beam width processing and polarimetric interferometric scattering phase center separation, and more over, the investigation on P band fully polarimetric SAR data processing aboard spaceborne platform suffered with the ionospheric effects was conducted. In detail they are:(1) With the IECAS P band fully polarimetric SAR system, the polarimetric scattering characters of corner reflector and natural targets were studied, and also the polarization calibration was implemented with triangle corner reflectors.(2) From the aspect of sub aperture processing, the variation of polarimetric character of surface under different sub apertures was investigated, and a data processing method based on two-element linear least square regression was presented for the underdetermined problem of DEM inversion with P band single pass polarimetric SAR data. The datasets acquired with IECAS P band fully polarimetric SAR were used in the validation of this data processing method.(3) Through the repeat pass PolInSAR data processing, the ground and volume scattering phase center separation was investigated, then a classification method based on the ground and volume scattering phase center separation was presented and validated with the repeat pass polarimetric interferometric data sets of IECAS P band SAR system.(4) Based on the observation of high ground to volume ratio of P band fully polarimetric data, an optimum baseline design method named"phase tube" with wide adaptability was presented from the aspect of compromise between"minimum interferometric coherence"and"ground volume scattering phase center separation", and validated with PolSARpro simulator.(5) Aiming at the high sensitivity of P band signal to ionospheric effects during transferring in the ionosphere, the ionospheric effects on signal phase, polarization state and InSAR/PolInSAR coherence were investigated, and furthermore a spaceborne P band fully polarimetric SAR data processing method combining both Faraday rotation measurement and auto focus processing was presented from the aspect of Appleton-Hartree equation. By involving high precision geomagnetic information, the Faraday rotation effects and phase perturbation was combined with the parameter of Total Electron Content (TEC) to improve the focusing of spaceborne P band fully polarimetric SAR imaging. This method can avoid the problem of low resolution of TEC measurement with GPS, and is applicable for practice use.