基于全极化SAR的浙江衢山岛DEM信息提取

DEM generation and information extraction over Qushandao usingfull-polarization SAR image

数字高程模型(digital elevation model,DEM)是重要的地理信息,合成孔径雷达(synthetic aperture radar,SAR)是提取数字高程模型的有效手段之一。本文以浙江衢山岛部分地区为研究区,利用2013年11月27日的Radarsat-2四极化精细工作模式极化SAR数据计算了研究区方位向两相邻分辨单元之间的极化方位角偏移量,从极化方位角偏移量提取了方位向坡度信息,得到了研究区地形的高程数据,并利用实测数据对提取的DEM信息进行了精度检验。结果表明,在海岸带及近海岛礁区域,单景全极化雷达DEM测量是可行的,计算结果的平均相对误差为20%,造成误差的主要原因是海面杂波造成的起算面的改变以及植被的树枝叶层造成方位角的变化导致的高程计算偏差。

As digital elevation model is an important geographic information,SAR（synthetic aperture radar）is one of the most effective means in digital elevation model extracting.Radarsat-2fine full-polarization mode data（November 27,2013）over Qushandao in Zhejiang Province was used to figure out the polarization azimuth offset between two adjacent resolution cells,and then to extract the gradient information and terrain elevation.Finally,the accuracy of the digital elevation model was tested by the measured data,and it was found the average relative error was about 20%.The results show that the main causes of errors are the change of the terrain basement caused by the sea clutter and the elevation deviation caused by the leaves and boughs of the vegetative cover.