DEM构建中InSAR技术应用及其精度分析

发布时间：2018-03-26 21:37

本文选题：数字高程模型　切入点：合成孔径雷达　出处：《昆明理工大学》2017年硕士论文

【摘要】：数字高程模型(Digital Elevation Model),简称DEM,是以高程为地形属性,用一组有序数值阵列形式表示地面高程,用来描述地形表面形态属性的数字表达模型,是数字地形模型(Digital Elevation Model,简称DTM)的一个分支,其它各种地形特征值均可由此派生。因此,DEM在测绘、水文、气象、地貌、地质、土壤、工程建设等国民经济和国防建设以及人文和自然科学领域有着广泛的应用。合成孔径雷达干涉测量(InSAR,Synthetic Aperture Radar Interferometry)是一种利用合成孔径雷达获取的相位信息为信息源,获取地表三维信息及变化信息的一种对地观测技术。它首先通过合成孔径雷达系统的两幅天线同时观测(单轨模式)或两次平行观测(重复轨道模式),获取地面目标区域的两幅SAR图像,然后对两幅SAR影像进行干涉处理得到干涉图,最后利用复数影像像对成像时的几何关系,将相位信息转换为高程信息,即可获得每一地面分辨单元的高程,进而获取地面目标区域的数字高程模型。相对与传统测量手段而言,InSAR技术在获取大范围DEM方面有着巨大的潜力。本文采用Sentinel-1A卫星雷达数据为数据源,并对其进行了数据处理和分析,详细探讨了在InSAR技术获取数字高程模型过程中的核心技术研究。论文以江川县及星云湖周边区域为研究区域,以Sentinel-1卫星获取的数据为数据源,通过理论分析,数据处理,实验结果与分析等,研究了通过InSAR技术获取DEM的精度,分析了影响InSAR技术获取DEM精度的原因,对InSAR技术获取DEM的可行性进行了研究。完成论文过程中所做的主要工作如下:(1)详细了解了合成孔径雷达干涉测量的理论知识,深入理解了合成孔径雷达干涉测量技术的原理。(2)在理解合成孔径雷达干涉测量原理的基础上,给出了通过InSAR技术获取数字高程模型的流程图,并使用Sentinel-1A卫星数据,结合辅助数据生成了研究区域的DEM。(3)在利用合成孔径雷达干涉测量技术生成DEM的过程中,详细研究了主流的干涉图滤波方法。以滤波后干涉影像的相干性为标准,比较了不同滤波方法的适应性。(4)详细研究了几种相位解缠算法,分别用不同的相位解缠方法处理了干涉影像,并对解缠相位影像进行统计分析,比对了不同相位解缠方法的适用性。(5)以高精度的GDEM数据为标准,对实验生成的DEM数据进行了精度评价。(6)通过对合成孔径雷达干涉测量技术的数学模型研究,找出了本次实验所提取DEM精度不高的原因,并提出了解决方法。
[Abstract]:Digital Elevation Model (DEM) is a digital representation model that uses elevation as topographic attribute and uses a set of ordered numerical arrays to express ground elevation. It is used to describe the morphological properties of topographic surface. Is a branch of Digital terrain Model (DTMs), from which all other topographic characteristics can be derived. So Dem is in mapping, hydrology, meteorology, geomorphology, geology, soil, The national economy, national defense construction, humanities and natural sciences, such as engineering construction, are widely used in the field of synthetic Aperture Radar interferometry. Synthetic Aperture Radar (SAR) interferometry is a kind of information source, which uses the phase information obtained by synthetic Aperture Radar (SAR). Earth observation technique for obtaining 3D and variation information of the earth surface. First, it acquires the ground through two antennas of the synthetic Aperture Radar system simultaneously (monorail mode) or two parallel observations (repeat orbit mode). Two SAR images of the target area, Then the interferogram is obtained by interferometric processing of two SAR images. At last, the height of each ground resolution unit can be obtained by converting the phase information into elevation information by using the geometric relation of complex image pair imaging. Furthermore, the digital elevation model of the ground target area is obtained. Compared with the traditional measurement method, the DEM technology has great potential in obtaining large range of DEM. In this paper, the Sentinel-1A satellite radar data is used as the data source. The data processing and analysis are carried out, and the core technology in the process of obtaining digital elevation model by InSAR technology is discussed in detail. The paper takes Jiangchuan County and the surrounding area of Xingyun Lake as the research area, and takes the data obtained by Sentinel-1 satellite as the data source. Through theoretical analysis, data processing, experimental results and analysis, the accuracy of obtaining DEM by InSAR technology is studied, and the reasons that affect the accuracy of DEM by InSAR technology are analyzed. The feasibility of obtaining DEM by InSAR technology is studied. The main work in the process of completing the thesis is as follows: 1) the theoretical knowledge of SAR interferometry is understood in detail. On the basis of understanding the principle of synthetic Aperture Radar interferometry, the flow chart of acquiring digital elevation model by InSAR technology is given, and the Sentinel-1A satellite data is used. In the process of using SAR interferometry to generate DEM, the mainstream interferogram filtering method is studied in detail. The coherence of filtered interference image is taken as the standard. The adaptability of different filtering methods is compared. Several phase unwrapping algorithms are studied in detail. The interference images are treated with different phase unwrapping methods, and the unwrapping phase images are analyzed statistically. The applicability of different phase unwrapping methods is compared. (5) based on the high precision GDEM data, the accuracy of the experimental DEM data is evaluated. 6) the mathematical model of synthetic aperture radar interferometry is studied. The reason for the low precision of DEM extraction in this experiment was found out, and the solution was put forward.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P208;P237

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