利用InSAR技术获取三峡地区的数字高程模型

ACQUISITION OF DEM OF THREE GORGES AREA BY INSAR

利用先进的合成孔径雷达干涉测量 (InSAR)技术 ,使用 38幅 1992～ 2 0 0 0年间三峡地区的ERS卫星SAR图像 ,并利用USGS的低精度DEM ,得到了该地区的DEM ,与GPS高程结果对比的差值为 15～ 12 8m。干涉结果表明 ,基线小于 2 0 0m的串行数据图像对具有较好的相干性 ;基线大于 2 0 0m、在晚春和夏季观测的串行数据图像对容易出现失相关 ,而几乎所有重复轨道的SAR图像对在进行配准时都不相关。为了进一步获得三峡地区较高精度的数字高程模型 ,在该地区建立了角反射器 。

We have derived the DEM of the Three Gorges area by using InSAR technique,in particular,38 European Remote Sensing (ERS) synthetic aperture radar (SAR) imagery in 1992-2000 and based on coarse 30 arc USGS DEMs.The InSAR derived DEM has 15～128 meters of difference with GPS derived height in vertical direction.The results show that all ERS tandem image pairs with baseline less than 200 meters have good coherences. Other tandem data sets which have baselines of over 200 meters and were acquired in later spring and summer are subject to decorrelation. Almost all of the repeat pass SAR data lost coherence during registering, even for some data sets observed at the same season. A corner reflector has been established in this area in order to improve the DEM accuracy. This study has set up a good foundation for further research and monitoring the geological disaster and crustal deformation in the Three Gorges area.