Analysis on the Transmit Distortion of the Circular Polarized Wave Based on the Axial Ratio Parameter

Abstract

Compact Polarimetric (CP) mode is a new dual-pol mode introduced in the last decade. The main current CP mode transmits circular polarized waves. Data in the form of Stokes parameters obtained by this mode has rotational invariance. In real engineering applications, transmit distortions in all dual-pol modes, including the CP mode, cannot be directly compensated with external calibration methods. Therefore, it is necessary to analysis the influences caused by transmit distortions. Until now, the Maximum Normalized Error (MNE) parameter has already been proposed by existing researches to analyze polarimetric quality of the Polarimetric SAR (PolSAR) system. This paper has proposed an analysis method to analysis the influence of transmit distortions in polarimetric modes with circular polarimetric wave in transmission, based on the Axial Ratio (AR) parameter of real transmitted wave. Firstly, this paper has analyzed the influence of different transmit distortion sources to AR parameter with simulations. Meanwhile, this part has also demonstrated the influence of same distortion sources to the MNE parameter. Through comparison of this two results, this paper has concluded three advantages of the AR parameter over the MNE parameter. At last, the effectiveness of the proposed evaluation method has been verified using real measured GF-3 distortion data and test data obtained by experimental system, which transmit circular polarized waves.

Keywords

• polarimetric sar (polsar)
• compact polarimetry (cp)
• axial ratio (ar)
• transmit distortion
• maximum normalized error (mne)