Title :
Calibration of Polarimetric PALSAR Imagery Affected by Faraday Rotation Using Polarization Orientation
Author_Institution :
Fac. of Eng., Dept. of Electr. & Electron. Eng., Gifu Univ., Gifu, Japan
Abstract :
For spaceborne polarimetric synthetic aperture radar (SAR), it is important to ensure the removal of both polarimetric system distortion and the effect of Faraday rotation. This paper proposes a new calibration method to derive the system distortion using polarization orientation (PO) induced in built-up areas and applies to Phased-Array-Type L-Band SAR (PALSAR) calibration. Faraday rotation is corrected by the circular-polarization-based method from the distortion matrix (DM)-calibrated data. The derived DMs do not coincide with those by the Japan Aerospace Exploration Agency (JAXA), but our calibration results compare well to JAXA´s results in PO angles and calibrator´s responses. The two results satisfy polarimetric calibration requirements, and the cross-polarized isolation improves by more than 5 dB after Faraday rotation correction following DM calibration-even in the case of small Faraday rotation (-2deg to -0.5deg). The proposed method is robust to noise and is useful when using an area of mixed polarimetric response for calibration. This method is also applicable to a large crosstalk system and the case of large Faraday rotation.
Keywords :
Faraday effect; calibration; geophysical techniques; measurement standards; radar polarimetry; spaceborne radar; synthetic aperture radar; Faraday rotation correction; Faraday rotation effect; Japan Aerospace Exploration Agency; Phased-Array-Type L-Band SAR; calibration method; circular-polarization-based method; crosstalk system; distortion matrix calibrated data; polarimetric PALSAR imagery calibration; polarimetric system distortion model; polarization orientation; spaceborne polarimetric synthetic aperture radar; Faraday rotation; Phased-Array-Type L-Band Synthetic Aperture Radar (PALSAR); polarimetric calibration; polarization orientation (PO); urban area;
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
DOI :
10.1109/TGRS.2009.2028692