InSAR时空基线对DEM精度的影响分析

Impact Analysis of InSAR Spatio-temporal Baseline on DEM Accuracy

In SAR是获取全球DEM的重要手段。然而In SAR地形测绘过程中极易受各类干涉要素的影响,其中基线是重要的干涉要素之一。本文采用天津地区40景Terra SAR-X影像构成的780个干涉对,定量分析了时空基线对In SAR地形测绘的影响,试验结果表明,空间基线越大,高程精度越高,两者呈幂函数关系;时间基线越大,高程精度越低,两者呈线性函数关系。因此在地形测绘过程中,应在确保相干性的前提下采用尽量长的空间基线,同时确保足够短的时间基线,消除时间失相干的影响。本文为国产SAR卫星的构型设计提供了技术参考。

InSAR is an important method of acquiring global DEM.However,the InSAR topographic mapping processing is affected by various interferometric factors,in which baseline is one of the most important elements. We quantitatively analyzed the effect of spatiotemporal baseline in InSAR topographic mapping,and analyzed 40 Terra SAR-X images of Tianjin which composed 780 interferograms after image processing.The experimental results show that the larger spatial baseline is,the higher the accuracy of elevation is,and there is a power function relationship.There is a linear function relationship between temporal baseline and accuracy of elevation,and great temporal baseline comes low accuracy of elevation. Therefore,in the process of topographic mapping,it is necessary to use the longest spatial baseline as long as the coherence is ensured,while ensuring a short temporal baseline in order to eliminate time decorrelation.This paper provides technical reference for the configuration design of homemade SAR satellite.