地基雷达大气改正方法及其应用于滑坡形变监测

发布时间：2017-12-27 10:08

本文关键词：地基雷达大气改正方法及其应用于滑坡形变监测　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：滑坡是我国频发的一种自然灾害,它的产生一方面是受地震、火山、大陆板块移动、降雨等自然因素的影响,另一方面随着城市化和全球化进程的发展,人类对地质环境的破坏日益加剧,人为因素诱发的滑坡增多且造成更大的损失和破坏。滑坡灾害一旦发生,会给周边区域人民的生命财产和国家的经济建设造成严重的损失,因此有必要对潜在的滑坡体的形变信息进行准确、及时的监测,从而能够采取相应的预警预防措施。现有的滑坡形变监测技术在滑坡监测中存在诸多不足,上世纪九十年代诞生的地基合成孔径干涉雷达(简称地基雷达)技术能够全天时、全天候、远距离、高精度地对大范围的监测区域实施连续监测,已经在滑坡形变监测中展现出巨大的应用前景和经济价值,从而掀开了滑坡形变监测新的篇章。开展地基雷达形变监测研究,有助于推广地基雷达滑坡形变监测应用,对于滑坡防灾减灾具有重要的意义。在理想观测条件下,地基雷达形变监测的精度很高;但在实际观测中,地基雷达传感器发射的电磁波信号受大气效应的影响会产生大气相位误差,降低了地基雷达监测结果的精度和可信性,因此有必要对地基雷达的监测结果进行大气改正,保证监测结果的精度和可靠性。由于大气环境的复杂性,国际上还没有统一的地基雷达大气改正,各种大气改正方法缺乏系统性的精度评定和普适性研究,鉴于此,本论文从归纳现有的地基雷达大气改正方法入手,采用理论与实验相结合的方法对大气改正方法的精度和普适性展开较为系统的分析。在此基础上,本论文针对距离函数拟合法存在的不足加以改进,提出了一种反距离大气改正方法,采用模拟实验和硗碛水库滑坡监测对该方法的精度和可行性进行检验。本论文的主要工作如下:(1)针对地基雷达各种大气改正方法缺乏系统的精度对比和普适性分析的问题,本论文比较系统地讨论和分析了地雷雷达最常用的气象数据改正法和距离函数拟合法在良好天气条件和不良天气条件下的精度和普适性。(2)针对距离函数拟合法存在未考虑方位向大气效应误差和控制点难以选取的两个不足,提出了一种改进的基于反距离加权的大气改正方法。详细阐述了该方法的基本原理和大气改正流程,并通过模拟实验证实:该方法有较高的大气改正精度和可行性。(3)本论文进一步分析了提出的大气改正方法在野外滑坡形变监测应用中精度和可行性。本论文用地基合成孔径雷达对雅安硗碛水库边坡进行连续监测,该区域地形梯度较大,地质构造被地震严重破坏,再加上常年受降雨和水库水流冲刷,滑坡地质灾害频发。采用本文提出的反距离加权方法对监测数据进行大气改正,结合该区域地面GPS滑坡监测结果做参照对监测区域的边坡稳定性进行分析。实验结果表明:该处边坡有两块区域形变特征较为明显,需要重点防范和加固,反距离加权大气改正方法在野外滑坡监测实际应用中具有较高的精度和可行性。
[Abstract]:Landslide is one of China's natural disasters, on the one hand, it is affected by the earthquake, volcano, continental plate, rainfall and other natural factors, on the other hand, with the development of city and the process of globalization, the human destruction of the geological environment increasing, people more loss and damage factors landslides caused by increased and. Once landslide occurs, it will cause serious losses to the life and property of the surrounding area and the economic construction of the country. Therefore, it is necessary to monitor the potential deformation information accurately and timely, so that we can take corresponding precautionary measures. The landslide deformation monitoring technology of the existing deficiencies in landslide monitoring, the foundation of synthetic aperture radar interferometry of the last century was born in 90s (the ground radar) technology can all day long and all-weather, long distance, high precision monitoring for a wide range of implementation of continuous monitoring, has shown great application prospects and economic value in the landslide deformation monitoring, which opened a new chapter in landslide deformation monitoring. The research of ground radar deformation monitoring is helpful to popularize the application of ground radar landslide deformation monitoring, which is of great significance for landslide prevention and reduction. In perfect observation conditions, deformation monitoring precision of ground radar is very high; but in the actual observations, the electromagnetic wave signal of ground radar sensor emission is influenced by the atmospheric effect can produce atmospheric phase errors, reduce the monitoring results of radar foundation accuracy and credibility, so it is necessary to monitor the results of atmospheric correction of ground-based radar. To ensure the accuracy and reliability of the monitoring results. Because of the complexity of the atmospheric environment, the international community has not yet unified ground radar atmospheric correction, various atmospheric correction methods lack of accuracy evaluation and general system of adaptability study, in view of this, this paper summarized from the existing ground-based radar atmospheric correction method of systematic analysis on applicability by using the method of combination of theory and experiment the atmospheric correction accuracy and P. On this basis, this thesis intends to lack the legal existence of the distance function is improved, the improvement method is proposed for inverse distance atmosphere, the accuracy and feasibility of simulation experiment and Qiaoqi reservoir landslide monitoring on the method of inspection. The main work of this paper are as follows: (1) according to the ground-based radar of various atmospheric correction methods lack of suitable analysis system and general accuracy comparison problems, this paper systematically discusses and analyzes the meteorological data of mine radar most commonly used correction and distance function fitting in good weather conditions and adverse weather conditions, the accuracy of and universal. (2) aiming at the two shortcomings of the distance function fitting method, which are not considering the error of azimuth atmospheric effect and the difficult selection of control points, an improved atmospheric correction method based on inverse distance weighting is proposed. The basic principle of the method and the atmospheric correction flow are described in detail. It is proved by the simulation experiment that the method has high accuracy and feasibility of atmospheric correction. (3) this paper further analyzes the accuracy and feasibility of the proposed atmospheric correction method in the application of the field landslide deformation monitoring. This paper using a ground-based synthetic aperture radar in Ya'an Qiaoqi reservoir slope for continuous monitoring, the terrain gradient is larger, the geological structure by the earthquake severely damaged, coupled with the perennial rainfall and reservoir water erosion, landslide geological disasters. The inverse distance weighted method proposed in this paper is used for atmospheric correction of monitoring data. Combined with the monitoring results of land GPS landslide in the area, the slope stability of monitoring area is analyzed. The experimental results show that there are two zones in the slope, and the deformation characteristics are obvious. We need to focus on prevention and reinforcement. The inverse distance weighted atmospheric correction method has high accuracy and feasibility in the practical application of the field landslide monitoring.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.22;P225.1

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