Calibration Techniques For The Multi-polarization Synthetic Aperture Radar

There is an urgent need for the polarimetric synthetic aperture radar(SAR) data to be calibrated, so that the quantitative relationships between radar backscatter and geophysical parameters can be properly established, along with the development of international polarimetric SAR technology and more and more in-depth study and application of polarimetric SAR data. Up to now a lot of polarimetric SAR calibration methods have been developed. Some of them have been used in several applied SAR systems and the calibration results are satisfying. However, the polarimetric SAR calibration technology has not been studied extensively and intensively in our country, therefore it is necessary to study it.In this paper, basic concept, scientific requirement and goal of polarimetric SAR calibration are reviewed. Exsiting calibration methods are classified as (1 ) methods using point targets and distributed targets; (2) methods using only distributed targets and (3) methods using only point targets. Then the typical algorithms of every methods are given in which those of method (1) and (2) are modified based on a quantity of literatures. And then the theoretical performances of these algorithms are analyzed. Finally, these algorithms are applied in L-band polarimetric data obtained by SIR-C system. The calibration results of every algorithms and the comparison of these results are given in the paper. From the experiments the performance of these algorithms are verified.At the end of the paper, based on the research work in this paper, it is stated the viewpoint of mine about the development of plolarimetric SAR calibration technology in our country.