城市重大工程区高分辨率永久散射体雷达干涉地表形变监测

发布时间：2018-09-12 20:41

【摘要】：随着城市的快速发展,高层建筑、轨道交通、高铁、高架道路等重大工程成为维系城市功能的基础性工程,为了避免和减少地面沉降对其造成影响和危害,亟需一种科学、高效的监测手段。近年来,差分合成孔径雷达干涉测量(D-InSAR)技术在地表形变监测中的应用发展很快。特别是以永久散射体干涉测量(PSI)方法为代表的D-InSAR时序分析方法,极大增强了D-InSAR技术在城市地面沉降监测中的应用能力。随着新型高时空分辨能力的雷达卫星不断发射升空,使得利用高分辨率PSI技术进行城市重大工程区的精细形变监测成为可能,但在实际应用中还存在较多问题。最主要的困难是在缺乏高精度城市数字地表模型(DSM)条件下,如何解决建筑物和背景地物之间在长基线条件下形成的高相位梯度问题。另外,如何更好的对雷达坐标表示的高分辨率城市地区PS点群进行可视化也是需要考虑的问题。针对上述问题,本文开展了城市重大工程区高分辨率PSI地表形变监测关键技术研究,取得以下主要成果： (1)对PSI差分相位建模和时域相位解缠策略上进行改进,提出了长短基线迭代组合的PSI解算方法。实验结果表明本文提出的方法能显著抑制高相位梯度对高程和形变提取结果的影响,具备城市大范围高层建筑密集区高程和形变监测的能力。 (2)对传统的PS点构网方式进行改进,提出了建筑物和背景地物分离构网的PSI解算方法。与长短基线迭代方法相比,该方法能够有效监测建筑物细微的形变特征,提高单体建筑形变监测的细节精度。但受限于分离技术,更适用于小范围内独立建筑物的精细监测。 (3)采用基于距离多普勒(R-D)定位模型的几何粗校正和以SPOT5为参考影像的几何精校正方法对PS点进行地理编码。实验表明,在x和y两个方向上的误差分辨单元都控制在1个像元以内,能够满足PS点地理编码的精度要求。另外,提出了独立建筑物上PS点的高程恢复算法,在ArcGlobe平台实现了PS点三维可视化。 (4)采用长短基线迭代的PSI方法对上海中心城区进行地表形变分析,结果表现出由大规模工程建设引起的沉降“小漏斗”特征,获得的结果与水准地面测量结果基本吻合。与ENVISAT获取的沉降结果对比分析,发现两者在城市地面沉降中心识别和监测能力上存在一致性,但是,由于CSK的点位密度更高,对沉降中心的最大沉降量监测更为准确。对地面沉降与城市建设相关分析表明,不断增加的建筑物载荷和地铁建设对地面沉降的贡献不容忽视。 (5)采用建筑物和背景地物分离的PSI方法对上海地铁10号线建设沿线的3栋高层建筑进行了精细监测,并实现了独立建筑物四维信息的表达。实验结果表明,与低层建筑物相比,高层建筑沉降不明显,受地铁开挖影响较小。本文的主要创新点有：(1)提出长短基线迭代组合的PSI方法,为城市建筑密集区大范围的地表形变监测提供了新的途径。(2)提出建筑物和背景地物分离的PSI方法,为小范围内独立建筑物的精细监测提供了新的方法。(3)利用R-D定位模型和参考影像的几何校正方法对PS点进行地理编码,提高了PS点地理编码的精度。提出独立建筑物上PS点的高程恢复算法,实现了PS点的三维可视化展示,从而更容易发现建筑体形变规律。
[Abstract]:With the rapid development of the city, high-rise buildings, rail transit, high-speed rail, elevated roads and other major projects have become basic projects to maintain the city's functions. In order to avoid and reduce the impact and harm caused by land subsidence, a scientific and efficient monitoring method is urgently needed. In recent years, differential synthetic aperture radar interferometry (D-InSAR) technology has been used. The application of D-InSAR time series analysis method, especially the Permanent Scatter Interferometry (PSI) method, has greatly enhanced the application ability of D-InSAR technology in urban land subsidence monitoring. The main difficulty is how to solve the problem of high phase gradient between buildings and background objects under the condition of long baseline without high precision urban digital terrain model (DSM). Good visualization of PS points in high resolution urban areas represented by radar coordinates is also a problem to be considered.
In view of the above problems, this paper studies the key technologies of high resolution PSI surface deformation monitoring in major urban engineering areas, and achieves the following main results:
(1) The PSI differential phase modeling and time domain phase unwrapping strategy are improved, and the PSI algorithm based on long and short baselines iteration combination is proposed. The experimental results show that the proposed method can significantly suppress the influence of high phase gradient on the results of elevation and deformation extraction, and can be used to monitor the elevation and deformation of large-scale high-rise buildings in urban areas. Ability.
(2) To improve the traditional PS dot netting method, a PSI method for separating buildings and background objects is proposed. Compared with the long-short baseline iteration method, this method can effectively monitor the fine deformation characteristics of buildings and improve the precision of deformation monitoring of single building. However, limited by the separation technology, it is more suitable for a small area alone. Fine monitoring of buildings.
(3) Geographic coding of PS points is carried out by using rough geometric correction based on range Doppler (R-D) positioning model and precise geometric correction based on SPOT5 reference image. Experiments show that the error resolution units in both X and Y directions are controlled within one pixel, which can meet the accuracy requirements of geocoding of PS points. The height recovery algorithm of PS points on buildings is realized, and the 3D visualization of PS points is realized on the ArcGlobe platform.
(4) The long-short baseline iteration PSI method is used to analyze the surface deformation in the central area of Shanghai. The results show that the settlement caused by large-scale engineering construction is "small funnel" and the results are basically consistent with the leveling ground survey results. There is consistency in identifying and monitoring capacity, but because of the higher point density of CSK, it is more accurate to monitor the maximum settlement of settlement center.
(5) Three high-rise buildings along Shanghai Metro Line 10 were carefully monitored by PSI method with the separation of buildings and background objects, and the four-dimensional information of independent buildings was expressed.
The main innovations of this paper are as follows: (1) The PSI method of long-short baseline iteration combination is proposed, which provides a new way for large-scale surface deformation monitoring in urban building-intensive areas. (2) The PSI method of separating buildings from background objects is proposed, which provides a new method for fine monitoring of small-scale independent buildings. (3) The R-D positioning model and the R-D positioning model are used. Geometric correction method of reference image is used to geocoding PS points, which improves the precision of geocoding. A height recovery algorithm of PS points on independent buildings is proposed, which realizes 3D visualization display of PS points, so it is easier to find the deformation law of buildings.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P225.1;TU196

【参考文献】