Visual interpretation of F.C.C. satellite data for channel migration and water logging conditions along Ghaghra and Terhi rivers in part of district Gonda and Bahraich,U.P.

The conventional visual interpretation of landsat Imagery is potentially the most useful remote sensing tool for the study of channel migration & water logging conditions at different time spans; which were earlier not easy due to non availability of suitable evidences. The present study brings out, in exact terms & the extent of the utility of the false colour and black and white landsat data. The application of the false colour scanning method is also useful remote sensing tool for the study of direct & indirect hydrogeological regime by visual interpretation technique. The spectrum are favourable for detection of surface phenomenon, which is associated with the subsurface ground water environment. An area of about 3,500 Sq.Km. of U.P. along left bank of Ghaghra river and right bank of Terhi rivers have been taken for the study. The paper was designed to evaluate the fluvial action and ground water environments with the help of repetitive landsat data in ten years. The fluvial action of Ghaghra and Terhi rivers have been mainly contributing to the development of hydrogeomorphological units which have given exact references regarding fluctuation in hydrogeomorphological units and water logging with hydrological response of the ground water environment, by using landsat data of 1975 & 1984. Further the direct relationship between remote sensing measurement and physical properties of hydrogeological environments is brought out in the maps.     

机载SAR图像定向参数的F．LDT解法

从SAR图像的F.Leberl构像模型出发，推导了成像载体匀速运动条件下的SAR图像定向参数的直接变找（Direct Transformation for F.Leberl Model。F.LDT）解法。通过比较F.LDT解法与F.Leberl构像方程线性代迭代解法的实验结果，得出结论：F.LDT解法可以满足精度要求，且无需初值，不需迭代，计算过程简单，避免了线性化迭代方法不收敛的情况。最后对影响F.LDT解法精度的因素进行了分析。     

机载SAR图像定向参数的F.LDT解法

从SAR图像的F.Leberl构像模型出发,推导了成像载体匀速运动条件下的SAR图像定向参数的直接变换(Direct Transformation for F.Leberl Model,F.LDT)解法.通过比较F.LDT解法与F.Leberl构像方程线性化迭代解法的实验结果,得出结论:F.LDT解法可以满足精度要求,且无需初值,不需迭代,计算过程简单,避免了线性化迭代方法不收敛的情况.最后对影响F.LDT解法精度的因素进行了分析.     

基于F.Leberl模型机载SAR影像联合平差

机载SAR影像定位时需要进行影像的联合平差,而传统的定位方法需要在地面控制条件较好的情况下才能进行平差。因此采用少量的地面控制点完成影像定位是我们需要研究的问题。论文基于F.Leberl构像模型研究了在控制点较少的情况下进行机载SAR影像联合平差的理论与方法。实验中分别对两景影像和四景影像进行联合平差,实验结果表明随着加密点数量的增加,加密点的精度有所提高,多景影像的联合平差可以减少地面控制点的数量,从而实现稀少控制点条件下的机载SAR影像高精度定位。     

基于F.Leberl改进模型的星载SAR影像精纠正

介绍SAR影像的F.Lebrl几何模型,分析星载条件下零多普勒条件不满足的原因,重点提出利用距离向像坐标ys的多项式拟合多普勒中心频率的方法修正零多普勒条件方程,建立星载SAR影像严格的F.Leberl模型,最后阐述利用改进的F.Leberl模型纠正SAR影像的具体步骤.ERS卫星影像的实验结果表明,提出的F.Leberl改进模型在检查点上可达到距离向2.1像素、方位向1.6像素的定位精度.