基于气象数据辅助的GB-InSAR大气相位补偿方法

GB-InSAR Atmospheric Phase Compensation Method Based on Meteorological Data

  • 摘要: 地基干涉合成孔径雷达GB-InSAR(Ground-Based Interferometric Synthetic Aperture Radar)测量中,大气相位是主要测量误差源之一。对于大气相位非线性变化的干涉相位图,常规的基于参数模型的补偿方法不再适用。该文提出一种基于气象数据辅助的GB-InSAR大气相位补偿方法,对于多幅GB-InSAR图像,首先基于折射率经验模型,利用气象数据估计出大气相位曲线,其次与PS(Permanent Scatterer,永久散射体)点的实际干涉曲线进行互相关运算,通过设定合理的门限实现稳定PS点的选择。然后利用稳定PS点,采用局部加权回归(locally weighted scatterplot smoothing,Lowess)、线性插值、神经网络3种插值拟合方法进行大气相位估计。最后对比补偿结果,选择最合适的插值拟合方案。实验结果表明,当PS点数量足够多时,3种方案均能有效补偿非线性大气相位分量。当区域内PS点数量较少时,采用Lowess方法的补偿效果最好。

     

    Abstract: Atmospheric phase (AP) is one of the main error sources in the measurement of GB-InSAR (Ground-based Interferometric Synthetic Aperture Radar). Nonlinear AP in the GB-InSAR interferogram cannot be effectively compensated with conventional parametrical models. This paper proposes an AP compensation method based on meteorological data. Firstly, based on the empirical model of refractive index, AP curves of all the PSs (Permanent Scatterers) are estimated through meteorological data. Then, the cross-correlations between the estimated AP curves and the measured interferometric phase curves are calculated. Those stable PSs are selected by setting a proper coherence threshold. Based on the stable PSs, three different interpolation fitting methods, including locally weighted scatterplot smoothing (Lowess), linear interpolation and neural network, are utilized to estimate the AP curves of all the PSs. The most appropriate interpolation fitting method is finally determined by comparing compensation results. Experimental results prove that when the PS number is enough, three methods can all effectively compensate the nonlinear AP components, or the Lowess method could achieve the best compensation performance.

     

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