An Approach to Determine the Maximum Acceptable Distortion Level in Polarimetric Calibration for Pol-InSAR Applications
Yongsheng Zhou(1), Wen Hong(1) and Fang Cao(1)
(1) Inst of Electronics, Chinese Academy of Sciences, No.19, Bei Si Huan Xi Lu, 100190 Beijing, China
The study described in this paper is an attempt at determining calibration requirements for Pol-InSAR applications, i.e., assessing the maximum acceptable distortion level.
SAR calibration accuracy is key factor in the quantitative use of SAR data as well as the design of future SAR system. Regarding Pol-InSAR, Cloude has analyzed the effect of miscalibration on the performance of the model based parameter estimation in forestry applications . We now focus on the calibration accuracy required for the Pol-InSAR applications. It is based on the approach introduced by Dubois et al. , which was used in determination of PolSAR calibration accuracy.
The calibration model and the effect of miscalibration on the Pol-InSAR observables are presented firstly. Then the approach to determine calibration requirements for Pol-InSAR vegetation parameter estimation is given. For given vegetation parameters (e.g. mean height, extinction coefficient), Pol-InSAR data are simulated based on the RVoG model. Calibration errors are added into the simulated data based on the calibration model. With the distorted Pol-InSAR data, the three-stage inversion process for vegetation parameter estimation  is performed. The relations between the estimation accuracy and calibration errors are derived. Based on analysis of the relations, the calibration accuracy requirements are given. Furthermore, this approach is validated using Pol-InSAR data.
 Cloude S. R., Calibration requirements for forest parameter estimation using POLinSAR, Proc. CEOS Working Group on Calibration/Validation - SAR Workshop, London, United Kingdom, 151-158, 2002.
 Dubois P. C., Evans D., and van Zyl J. J., Approach to derivation of SIR-C science requirements for calibration, IEEE Transactions on Geoscience and Remote Sensing, Vol. 30, 243-246, 1992.
 Cloude S. R. and Papathanassiou K. P., Three-stage inversion process for polarimetric SAR interferometry, IEE Proceedings: Radar, Sonar and Navigation, Vol. 150, 125-134, 2003.