Polarimetric calibration requirements for a classification scheme based on scattering type alpha

Polarimetric calibration is aimed at intercalibrating the polarization channels of the radar system. A better characterization of the target and of the backscattering mechanisms can be obtained by polarimetric calibration. The study described in this paper is an attempt at deriving the requirements on the polarimetric calibration for a commonly used classification method based on the scattering type alpha. A model representing the effects of the residual distortion of the polarimetric data after calibration is present. This distortion model is then applied to calculate alpha angle, through which the polarimetric calibration requirements for identifying seven scatterers can be obtained. We will show that, the phase of parameter f, representing the phase difference of the mismatch between the like-polarized channels, affects the classification results most significantly.