基于地形和GPS观测的SAR干涉图大气延迟估计

ATMOSPHERIC DELAY ESTIMATION OF SAR INTERFEROGRAM BASED ON GPS OBSERVATIONS AND TERRAIN

大气效应尤其是大气水汽含量在时间和空间上变化引起的雷达信号传播延迟,是重轨雷达干涉测量中难以消除的主要误差源之一。仅借助对GPS水汽的空间数学插值实现对InSAR中的大气延迟改正时,由于未能顾及地形对大气湿延迟的影响,导致改正效果较差。针对这一问题,分析了大气湿延迟中垂直分层部分与地形的关系,建立了两者间相关函数模型,进而提出了顾及地形影响的大气延迟插值新方法。实验结果表明:插值新方法较常规距离权倒数和克里格法,具有明显的优越性。

The radar signal propagation delay caused by atmospheric effects,especially atmospheric water vapor content changing in time and space,is one of the main error sources in repeat-pass interferometry SAR,which is difficult to eliminate and greatly limits the applications of differential interferometry SAR.When only GPS water vapor is considered for the atmospheric delay correction in InSAR,it is will be leading to poor effect of correction taking into account the impact of topography to atmospheric wet delay.The relationship between the terrain and vertical layered component of atmospheric wet delay was analyzed and a function model between them was established.On the basis of it,a new interpolation method is proposed,which takes into account the impact of terrain on atmospheric delay.The calculation results show that the new interpolation method has obvious advantages compared with IDW and Kriging methods.