Abstract: InSAR has been demonstrated to be a promising technology to map accurate DEM.However，if an InSAR system is configured with repeat-pass space borne SAR，vegetation，water vapor，baseline decorrelation and temporal decorrelation limit the accuracy of its applications.A pair of ERS-1/2 tandem SAR images is used to generate the interferogram and DEM in Zhenjiang area，followed by the accuracy analysis with respect to baseline and phase noise.The relation between phase noise and coherence，multilook is given.The results show that DEM error is less than 3.5 meters in small area if only the baseline and phase noise are considered.

Key words: Interferometric Synthetic Aperture Radar（InSAR）, Digital Elevation Model（DEM）, accuracy analysis

摘要： 星载合成孔径雷达干涉（InSAR）技术是一种数据覆盖范围广、廉价、高效、方便的数字高程模型（DEM）获取方法，但在地面植被覆盖广、大气水汽含量高的地区其影像相干性随时间基线的增加迅速降低；同时，SAR卫星的轨道误差也影响DEM精度。利用ERS-1/2卫星串行模式SAR数据获取镇江地区DEM，分析了轨道误差对DEM精度的影响；根据干涉相位的统计特性，从理论上给出干涉相位噪声与相干系数和视数之间的关系。实验结果表明就干涉像对的卫星轨道误差和相位噪声而言，在小区域内DEM精度优于3.5 m。

关键词: 合成孔径雷达干涉测量, 数字高程模型, 精度分析