地面沉降论文：PS探测方法的改进及其在天津地区沉降监测中的应用

1、地面沉降论文：PS探测方法的改进及其在天津地区沉降监测中的应用【中文摘要】由于受人为和自然因素的影响,地面沉降等各种地质灾害正逐步影响着人们的生活环境和人类社会、经济发展。随着城市化进程加快,人口快速集中,城市地区的地面沉降更加突出。在我国自上世纪20年代出现地面沉降以来,目前已发展成为区域性分布的格局。天津市受过度抽取地下水资源的影响已成华北地区的沉降中心。InSAR技术与传统的水准测量、GPS等监测地面沉降方式相比,具有覆盖广、全天候和低成本的优势,但传统D-InSAR技术在测绘地表沉降中受时空失相干和大气影响,无法适应长时间序列的缓慢地表形变的测量工作。PSInSAR技术提取区域中长时间

2、保持稳定、相位质量好的永久散射体来提取时间序列地表形变信息,克服了常规D-InSAR的不足。但是PSInSAR技术在PS点的选取、网形的构建方法和非线性估计等方面还需要完善,同时基于高分辨率TerraS AR影像的PS干涉技术应用也是一个新的课题。本文旨在对PSInSAR技术做局部改进的基础上,使用高分辨率影像获取了天津地区的地面沉降数值。具体有以下几方面的工作。1、本文在查阅大量文献的基础上对D-InSAR的技术原理和数据处理流程,以及实践应用进行了全面系统性的总结。对基于高相干性点目标分析技术监测长时间序列地表形变的代表方法进行了介绍。2、本文基于TerraSAR-X高分辨率数据对常用的P

3、S探测方法进行了实验研究,结果表明高分辨率数据可显著增加可探测PS点的数量,在实践中应对阈值的选择做适当调整。为了提高PS点的可靠性,本文提出基于时序在前面实验的基础上提出基于振幅离差指数和时序振幅均值统计中值阈值的PS探测方法。3、对于因限制Delaunay三角网边长而产生的孤立PS点,本文中采用最邻近连接(CCM)的方法,使这些孤立点与最近的PS相连接,达到PS网络闭合的。4、分析了传统等权最小二乘的稀疏PS点相位解缠方法的不足,对按相位梯度最小来设置权重,进行加权最小二乘相位解缠的方法进行了实验研究,并基于不同的噪声水平进行的仿真模拟实验,得到了可靠的实验结论。5、采用2009年3月至2

4、010年11月的17幅TerraSAR-X数据,采用改进的PSInSAR技术获取了天津地区的地面沉降数据,并与地面水准数据进行了验证。结果表明本文使用的方法切实可行,所获取的沉降监测结果可靠。【英文摘要】Geographical disasters, man-made or natural, like land subsidence, are influencing peoples living environment and development of human society and economy. With the speeding up of urbanization, larg

5、e quantities of population flooded into cities, where land subsidence became more serous. China detected land subsidence in 1920s, and now this problem has developed into a region-distributed phenomenon. Tianjin City has become the center of subsidence in North China due to the over-drained groundwa

6、ter.Compared with traditional leveling and GPS, InSAR technique has more advantages like better coverage and lower cost, and it can work for all-weather condition to monitor land subsidence. But traditional D-InSAR is liable to be influenced by decorrelation and atmosphere delay influence in mapping

7、 land subsidence, thus unable to be applied to slow deformation measurement of surface for a long time. On the other hand, PSInSAR technique is able to extract long-time stable permanent scatterers with good-qualitied phases to acquire time series of surface deformation information, which has overco

8、med the disadvantage of traditional D-InSAR. But PSInSAR technique needs to be perfected in the choosing of PS points, net-shaped construction method and nonlinear deformation estimation and so on. Meanwhile, Interferomtric technology of PS based on high resolution TerraSAR images is a new subject t

9、oo.This paper aims to acquire the value of land subsidence in Tianjian area by analyzing high resolution images, with some improvement to PSInSAR technique. The job includes the following parts:1.This paper is to analyze D-InSAR technique, its data-processing procedure and its application in practic

10、e in details based on a large amount of reviewed references. Then the paper is to introduce the representative ways based on high coherence point target analysis to monitor long-time series of surface deformation.2.This paper is based on the experimental research on TerraSAR-X high resolution data,

11、which explores regular PS detection method. The results show that high resolution data can dramatically increase the number of PS points, and in practice the choice of thresholds should be adjusted. In order to improve the reliability of PS points, this paper has improved the PS detection method on

12、the basis of initial experiment.3.As to the isolated PS points caused by restricted Delaunay triangle side, this paper is to adopt the method of closest connection method(CCM) which connects these isolated points with their closest PS so as to achieve the PS network closure. 4.After analyse the disa

13、dvantage of traditional unweighted Least Squares, phase gradient minimum criterion being used to set the weight, the weighted least squares phase unwrapping methods were studied through the simulation. Simulation experiment based on different levels of noise has been a reliable test conclusion.5.Thi

14、s paper is to extract the land subsidence data of Tianjian by analyzing 17 TerraSAR-X images scanned from March 2009 to Nov.2010 and adopting improved PSInSAR technique. The data are compared with the ground-level data, which indicates that this method works and the obtained subsidence data is relia

15、ble.【关键词】地面沉降 TerraSAR-X 永久散射体雷达干涉测量 PS探测【英文关键词】Land Subsidence TerraSAR-X PSInSAR PS detection【目录】PS探测方法的改进及其在天津地区沉降监测中的应用 摘要 6-7 Abstract 7-8 第1章 绪论 11-17 1.1 论文的研究意义 11-13 1.2 国内外研究现状 13-14 1.3 论文研究的主要内容 14-16 1.4 论文的组织结构 16-17 第2章 D-InSAR技术 17-35 2.1 InSAR的技术原理 17-20 2.2 单基线D-InSAR技术及其应用于地面沉降监测实

16、践 20-29 2.2.1 单基线D-InSAR技术原理 20-26 2.2.2 单基线D-InSAR监测地面沉降的实践 26-29 2.3 单基线D-InSAR技术局限性 29-31 2.3.1 空间几何失相干 30 2.3.2 时间失相干 30-31 2.3.3 大气影响 31 2.4 基于相干点目标分析的多基线D-InSAR方法 31-35 2.4.1 永久散射体(PS)方法 32-33 2.4.2 小基线子集(SBAS)方法 33 2.4.3 相干目标(CT)分析方法 33-35 第3章 PS点的探测实验及结果 35-51 3.1 参考影像的选取和SAR影像的配准 36-41 3.1.

17、1 配准参考影像的选取 36-37 3.1.2 SAR影像的配准 37-41 3.2 SAR影像的相对辐射校正 41-42 3.3 PS探测方法 42-49 3.3.1 相干系数阈值法 42-45 3.3.2 振幅离差指数阈值法 45-46 3.3.3 振幅和振幅离差指数双阈值法 46-47 3.3.4 振幅离差指数和时序振幅均值统计中值阈值的PS探测方法 47-49 3.4 干涉像对组合与干涉图生成 49-51 第4章 PS网络建模、参数求解与沉降量提取 51-74 4.1 PS差分网络的建立 51-53 4.2 PS邻域差分建模 53-59 4.2.1 PS邻域差分模型建立 53-55 4

18、.2.2 模型相关系数求解 55-59 4.3 参数估计 59-61 4.3.1 二维解空间搜索 59-60 4.3.2 邻域差分网络的优化 60-61 4.4 网络平差 61-63 4.5 残余相位计算 63 4.6 稀疏PS点相位解缠 63-69 4.6.1 InSAR相位解缠理论 63-64 4.6.2 二维规则格网数据的相位解缠方法概述 64 4.6.3 二维离散分布数据的相位解缠方法 64-65 4.6.4 基于加权最小二乘的稀疏PS点相位解缠方法 65-66 4.6.5 基于加权最小二乘的稀疏PS点相位解缠的仿真实验及其结果 66-69 4.7 PS离散点数据的空间插值 69-70 4.8