一种基于分布目标的PolSAR法拉第旋转角和通道不平衡参量的估计方法
doi: 10.3724/SP.J.1146.2007.00258
An Estimation Method of Faraday Rotation and Channel Imbalance of PolSAR Using Distributed Targets
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摘要: 星载极化SAR定标时除了考虑雷达系统本身的交叉耦合和通道不平衡f系统失真参数的校正外还需要考虑法拉第旋转角的校正问题。该文提出了一种利用分布目标统计特性估计法拉第旋转角和通道不平衡f的方法，该方法不需要预先知道所用目标的散射矩阵，而只需要两种不同类型分布目标满足互易性和不相关性。在实际应用中，同一场景内要找到满足要求的两种不同类型分布目标(如森林、草地、农田等)是比较容易的事情，因此该方法具有实际应用价值。该文还通过半物理仿真实验对该方法的有效性进行了验证。Abstract: Besides the crosstalk and channel imbalance f of SAR system, calibration of the spaceborne Polarimetric SAR(PolSAR) also needs to consider the correction of Faraday rotation. This paper proposes a method for estimating Faraday rotation and channel imbalance which uses the statistical characteristics of distributed targets. The method does not need to know the scattering matrixes and only requires that the two different distributed targets satisfy reciprocity and reflection symmetry. In practical applications, it would be easy to find two different kinds of distributed targets(such as forests, farmland or pasture) which meet the requirements in one scene of the SAR image. Therefore the method proposed here has practical values. Simulation experiment with real PolSAR data is carried out to validate the method.
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