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1.
极具潜力的空间对地观测新技术——合成孔径雷达干涉   总被引:33,自引:0,他引:33  
“合成孔径雷达干涉(InSAR)”是近十年发展起来的空间对地观测遥感新技术。它具有从覆盖同一地区的星载(或机载)合成孔径雷达复数图像对提取干涉相位图,借助于雷达成像时的姿态数据重建地表三维模型(即数字高程模型)的巨大潜力。尤其是基于多幅雷达复数图像处理的差分干涉技术(D-InSAR)可以用于监测地表形变,精度可达厘米级甚至更高,其监测空间分辨率是前所未有的。介绍了InSAR和D-InSAR的基本原理,对影响干涉结果的一些重要因素做了分析,重点回顾和展望了差分干涉技术在与地表形变有关的地震监测和震后形变测量、地面下沉和山体滑坡、火山运动监测等方面应用的现状和前景。  相似文献   

2.
Within the SLAM project (Service for Landslide Monitoring), launched in 2003 by the European Space Agency (ESA) the Permanent Scatterers (PS) technique, a multi-image interferometric approach, coupled with the interpretation of aerial-photos and optical satellite images, was carried out for landslide investigations. The PS analysis was applied at a regional scale as support for landslide inventory mapping and at local scale for the monitoring of single well-known slope movements. For the integration of the PS measurements within a landslide inventory the Arno river basin (Italy) was chosen as test site for the presence of a high number of mass movements (to date about 300 areas at high landslide risk and more than 27,000 individual landslides mapped by the institutional authorities). About 350 SAR images have been interferometrically processed by means of the PS technique, with the detection of about 600,000 PS. The use of optical images contributed spatial meaning to the point-wise information provided by the PS, making it easier to identify terrain features related to slope instability and the landslide boundaries. Here we describe the employed methodology and its impact in the updating of a preexisting landslide inventory. 6.8% of the total number of landslides were characterized by ground displacement measurements from the PS: 6.1% of already mapped landslides and 0.8% of new unstable areas detected through the PS analysis. Moreover, most of the PS are located in urban areas, showing that the proposed methodology is suitable for landslide mapping in areas with a quite high density of urbanization, but that over vegetated areas it still suffers from the limitations induced by the current space-borne SAR missions (e.g. temporal de-correlation). On the other hand, the use of InSAR for the monitoring of single slow landslides threatening built-up areas has provided satisfactory results, allowing the measurement of superficial deformations with high accuracy on the landslide sectors characterized by a good radar reflectivity and coherence.  相似文献   

3.
《Engineering Geology》2007,89(3-4):200-217
Within the SLAM project (Service for Landslide Monitoring), launched in 2003 by the European Space Agency (ESA) the Permanent Scatterers (PS) technique, a multi-image interferometric approach, coupled with the interpretation of aerial-photos and optical satellite images, was carried out for landslide investigations. The PS analysis was applied at a regional scale as support for landslide inventory mapping and at local scale for the monitoring of single well-known slope movements. For the integration of the PS measurements within a landslide inventory the Arno river basin (Italy) was chosen as test site for the presence of a high number of mass movements (to date about 300 areas at high landslide risk and more than 27,000 individual landslides mapped by the institutional authorities). About 350 SAR images have been interferometrically processed by means of the PS technique, with the detection of about 600,000 PS. The use of optical images contributed spatial meaning to the point-wise information provided by the PS, making it easier to identify terrain features related to slope instability and the landslide boundaries. Here we describe the employed methodology and its impact in the updating of a preexisting landslide inventory. 6.8% of the total number of landslides were characterized by ground displacement measurements from the PS: 6.1% of already mapped landslides and 0.8% of new unstable areas detected through the PS analysis. Moreover, most of the PS are located in urban areas, showing that the proposed methodology is suitable for landslide mapping in areas with a quite high density of urbanization, but that over vegetated areas it still suffers from the limitations induced by the current space-borne SAR missions (e.g. temporal de-correlation). On the other hand, the use of InSAR for the monitoring of single slow landslides threatening built-up areas has provided satisfactory results, allowing the measurement of superficial deformations with high accuracy on the landslide sectors characterized by a good radar reflectivity and coherence.  相似文献   

4.
In recent years SAR interferometry has become a widely used technique for measuring altitude and displacement of the surface of the earth. Both these capabilities are highly relevant for landslide susceptibility studies. Although there are many problems that make the use of SAR interferometry less suitable for landslide inventory mapping, it’s use in landslide monitoring and in the generation of input maps for landslide susceptibility assessment looks very promising. The present work attempts to evaluate the usefulness and limitations of this technique based on a case study in the Swiss Alps. Input maps were generated from ERS repeat pass data using SAR interferometry. A land cover map has been generated by image classification of multi-temporal SAR intensity images. An InSAR DEM was generated and a number of maps were derived from it, such as slope-, aspect, altitude- and slope form classes. These maps were used to generate landslide and rockfall susceptibility maps, which give fairly well acceptable results. However, a comparison of the InSAR DEM with the conventional Swisstopo DEM, indicated significant errors in the absolute height and slope angles derived from InSAR, especially along the ridges and in the valleys. These errors are caused by low coherence mostly due to layover and shadow effects. Visual comparison of stereo images created from hillshading maps and corresponding DEMs demonstrate that a considerable amount of topographic details have been lost in the InSAR-derived DEM. It is concluded that InSAR derived input maps are not ideal for landslide susceptibility assessment, but could be used if more accurate data is lacking.  相似文献   

5.
This paper is addressed to readers without advanced knowledge of remote sensing. It illustrates some current and potential uses of satellite Synthetic Aperture Radar interferometry (InSAR) for landslide assessment. Data acquired by SAR systems can provide 3D terrain models and be used to assist in regional scale investigations, e.g. aimed at evaluation of susceptibility of slopes to failure. Under favourable environmental conditions, the innovative Permanent Scatterers (PS) technique, which overcomes several limitations of conventional SAR differential interferometry (DInSAR) applications in landslide studies, is suitable for monitoring slope deformations with millimetric precision. The PS technique combines the wide-area coverage typical of satellite imagery with the capability of providing displacement data relative to individual image pixels. With the currently available radar satellites, however, only very slow ground surface displacements can be reliably detected and measured. The presented case study of a landslide from the Liechtenstein Alps indicates that the most attractive and reliable contribution provided by this remote sensing technique lies in the possibility of (i.) wide-area qualitative distinction between stable and unstable areas and (ii.) qualitative (relative) hazard zonation of large, slow landslides based on the identification of segments characterised by different movement rates. Since only the radar line of sight projection of the displacements can be detected, a quantitative exploitation of the PS data is possible only where sufficient ground truth is available. In site specific or single landslide investigations the PS data can represent a very useful complementary data source with respect to the information acquired through ground based observations and in situ surveying. However, the difficulties associated with the feasibility assessments of the applicability of SAR data to local scale problems, as well as with the interpretation of PS results, require a close collaboration between landslide experts and specialists in advanced processing of radar satellite data. The interpretation of the exact geotechnical significance of small, radar sensed ground surface deformations is challenging, especially where ground truth is lacking. Although any ground deformation is potentially of interest to an engineering geologist, detection of movements in both vertical and horizontal directions is needed in the case of landslides to evaluate slope failure mechanisms. With their high radar viewing angles, however, the current space-borne systems can detect only a fraction of the horizontal component of movement. It is expected that the upcoming SAR dedicated missions with new sensors and different acquisition geometries, combined with the rapid developments in the field of advanced radar data processing, will allow a full 3D reconstruction of deformation data and help to further reduce the current limitations of the PS and similar DInSAR approaches.  相似文献   

6.
利用InSAR技术研究黄土地区滑坡分布   总被引:1,自引:0,他引:1  
InSAR技术能够获取大面积、连续、高精度的地表垂直形变信息,可用来监测地震、火山、滑坡等自然灾害造成的地表形变。文章介绍了InSAR技术在监测陕北黄土地区滑坡中的应用,首先进行野外地质勘察和TM光学遥感影像解译,接着通过EnviSat SAR数据差分干涉处理,获取研究区干涉形变场,提取出滑坡位移量,最后详细分析黄草湾至董家寺沿线一带的滑坡变形范围,并划定出了4个有一定变形的重点监视区。  相似文献   

7.
基于合成孔径雷达干涉测量技术的地面沉降研究综述   总被引:2,自引:0,他引:2  
综述了合成孔径雷达干涉测量(InSAR)技术的研究现状及其在监测地面沉降方面的优势和缺陷.与传统监测方法相比,InSAR技术在地面沉降监测方面主要具有全天候、大范围、高分辨率、高精度等优势,但在实际应用中则会产生去相关问题.探讨了利用该技术监测地面沉降的发展方向,认为应将InSAR与GPS及传统的水准测量等方法结合使用,合理利用各技术之间的互补性.  相似文献   

8.
差分干涉SAR冻土形变检测方法研究   总被引:12,自引:4,他引:8  
李震  李新武  刘永智  任鑫 《冰川冻土》2004,26(4):389-396
季节性冻融导致的地表形变是冻土地区工程建设的主要病害,冻土的冻胀和融沉是影响青藏公路以及目前建设的青藏铁路路基稳定的重要因素.近年来,差分干涉测量技术已成为地表形变测量和监测的重要工具.基于重复轨道的ERS 1/2雷达图像,研究了利用干涉SAR技术探测冻土形变的方法,经过对引入DEM差分干涉SAR技术的处理和分析,得到研究区冻土形变结果.通过与实测数据比较,表明重轨差分干涉测量可以精确地探测冻土表面形变,可用于青藏铁路冻土形变监测.  相似文献   

9.
岩溶山区地质环境复杂且脆弱,重特大崩滑地质灾害时有发生。如果对岩溶山区的地质环境认知不准,将直接导致对灾害识别能力不足。文章围绕岩溶山区裸露型岩溶陡崖、复合岩组型斜坡以及非裸露型岩溶斜坡3类基本易滑地质结构差异,探讨多源数据条件下更具适用性的识别探测方法。对于空间影响面积小的厚层岩溶陡崖结构,星-地组合识别方法更加适用,基于GNSS的识别探测方式可在获得动态变形趋势基础上,对可能发生的失稳模式进行初步预判,同时可对InSAR解译的地表位移进行矢量化校正,有利于提高对具有相同或相近SAR数据条件地区的灾害识别程度。对于具有较大空间影响面积的斜坡区域,可优先选用基于InSAR的遥感技术来获取地表变形结果,对于有致灾风险的大变形区还可结合易滑地质结构及外部影响因素对其可能失稳模式进行预判或反演分析。任何灾害识别方式都有其局限性,在实践中可根据不同地质结构特征与灾害类型特点,通过多源、多维度监测来构建综合识别体系,探索更具适用性的识别探测与数据分析新思路。   相似文献   

10.
史绪国  徐金虎  蒋厚军  张路  廖明生 《地球科学》2019,44(12):4284-4292
坡体表面形变是表征坡体稳定性的重要信息,因此,非常有必要对滑坡多发区域进行时序常规变形监测.近年来,星载合成孔径雷达数据由于其覆盖范围大、形变监测精度高的特点,被越来越多的用于山区滑坡识别与探测.首先介绍了联合分布式目标与点目标的时序InSAR方法,并将该方法应用于分析覆盖三峡藕塘滑坡的2007年至2011年的19景ALOS PALSAR数据和2015年至2018年的47景Sentinel-1数据,提取了数据覆盖时间段内的藕塘地区的变形速率.发现相比于2007年至2011年,2015年至2018年新增三处不稳定斜坡.进一步对滑坡的时序变形分析表明,降雨和水位变化是坡体稳定性最大的两个影响因素.实验证明时序InSAR方法可以作为常规形变手段来识别与监测三峡库区等地区潜在的滑坡,为防灾减灾提供支持与依据.   相似文献   

11.
The application of satellite differential synthetic aperture radar (SAR) interferometry, principally coherent (InSAR) and to a lesser extent, persistent-scatterer (PSI) techniques to hydrogeologic studies has improved capabilities to map, monitor, analyze, and simulate groundwater flow, aquifer-system compaction and land subsidence. A number of investigations over the previous decade show how the spatially detailed images of ground displacements measured with InSAR have advanced hydrogeologic understanding, especially when a time series of images is used in conjunction with histories of changes in water levels and management practices. Important advances include: (1) identifying structural or lithostratigraphic boundaries (e.g. faults or transitional facies) of groundwater flow and deformation; (2) defining the material and hydraulic heterogeneity of deforming aquifer-systems; (3) estimating system properties (e.g. storage coefficients and hydraulic conductivities); and (4) constraining numerical models of groundwater flow, aquifer-system compaction, and land subsidence. As a component of an integrated approach to hydrogeologic monitoring and characterization of unconsolidated alluvial groundwater basins differential SAR interferometry contributes unique information that can facilitate improved management of groundwater resources. Future satellite SAR missions specifically designed for differential interferometry will enhance these contributions.  相似文献   

12.
作为大地测量的一种新兴空间技术,合成孔径雷达干涉(synthetic aperture radar interferometry, InSAR)具有全天时、高精度、大范围和速度快的优点,逐渐被应用于多年冻土区地表形变监测中。通过综述多年冻土形变原理及InSAR监测多年冻土形变的应用实例,研究表明:在气候变暖的背景下,多年冻土区地表年际形变以下沉为主,多年冻土上限附近地下冰含量的大小是影响年际形变量的主要因素;活动层内土壤含水量影响着地表季节形变量的大小,不同类型多年冻土区的地表年际形变量和季节形变量存在着较大的差异。研究还表明,不同波长的SAR产品在不同类型多年冻土区的适用性不同,下垫面特征对利用InSAR获取地表形变量有较大影响,L波段的SAR数据在植被覆盖度较好的区域有更好的效果。由于InSAR的失相干问题,加之目前还缺少长时间、多类型、高频率的实测形变结果作为验证和标校数据,获取准确且连续的大范围形变数据较为困难。针对目前寒区研究需求,布设野外长期观测站点,建立适用于不同多年冻土区的地表形变反演算法,构建具有较高精度和较高时空分辨率的地表形变数据集具有重要的实践和科学意义。  相似文献   

13.
该文详细论述与分析了合成孔径雷达干涉测量(InSAR)的干涉几何特征及InSAR影像之间的相关性特征,着重阐述并分析了影响其地学监测方面的数据质量等相干技术问题,就InSAR开展上海城市地面沉降研究提出了基本思路,对InSAR城市遥感应用的潜在意义进行了分析和讨论。  相似文献   

14.
Interferometric synthetic aperture radar (InSAR) analysis is a radar technique for generating large-area maps of ground deformation using differences in the phase of microwaves returning to a satellite. In recent years, high-resolution SAR sensors have been developed that enable small-scale slope deformation to be detected, such as the partial block movement of a landslide. The L-band SAR (PALSAR-2) is mounted on Advanced Land Observing Satellite-2 (ALOS-2), which was launched on 24 Mar. 2014. Its main improvements compared with ALOS are enhanced resolution of as high as 3 m with a high-frequency recurrence period (14 days). Owing to its high resolution and the use of the L-band, PALSAR-2 can obtain reflective data passing through a tree canopy surface, unlike the other synthetic aperture radars. Therefore, the coherence of InSAR in mountainous forest areas is less likely to decrease, making it advantageous for the extraction of slope movement. In this study, to verify the accuracy of InSAR analysis using PALSAR-2 data, we compared the results of InSAR analysis and the measurement of the displacement in a landslide by global navigation satellite system (GNSS) observation. It was found that the average difference between the displacements obtained by InSAR analysis and the field measurements by GNSS was only 15.1 mm in the slant range direction, indicating the high accuracy of InSAR analysis. Many of the areas detected by InSAR analysis corresponded to the locations of surface changes due to landslide activity. Additionally, in the areas detected by InSAR analysis using multiple datasets, the ground changes due to landslide movement were confirmed by site investigation.  相似文献   

15.
The central Kutch region of Gujarat, India, experienced a M7.7 earthquake on January 26, 2001, causing large-scale ground deformations including a huge loss of lives and infrastructure. The rupture of a hidden reverse fault was the reason for this intense tectonic activity. The post-seismic ground deformations, attributed to the relaxation phase of a stressed crustal layer, have been analyzed using a pair of Advanced Land Observation Satellite-Phased Array type L-band Synthetic Aperture Radar interferometric synthetic aperture radar (InSAR) images. The InSAR images were obtained in 2007 and 2010, covering an area around Bhuj. It falls on the Kutch Mainland Fault and Katrol Bhuj Fault. Using the ADORE-DORIS software, interferometric imagery has successfully been generated, covering the study area. This allowed making interesting geological inferences. Three different regions in the study area elicited countable visible colored fringes, indicating different amounts of positive and negative ground deformations (surface motion with respect to the satellite). They occurred within the InSAR data acquisition dates. The region around Bhuj and to the north and east of Bhuj showed top surface deformations of about 35, 35, and 24 cm, respectively. The synoptic view of the interferometric image of the study area suggests two crustal fault lines running to the north and south of Bhuj city. The Institute of Seismological Research, geophysical and Global Positioning System data, indicates that huge seismic events occurred during the year 2007–2010 and supports the observational inference of clustering of interferometric fringes to the E and NE of the study area.  相似文献   

16.
This paper presents two innovative methods for tunnel monitoring that are based on digital photogrammetry. Both have been conceived to speed up operations that are currently accomplished by using engineering geodesy techniques and instruments. On the same time, proposed solutions are cheap and affordable. The first one is aimed at measuring relative deformations of transversal cross-section of tunnels. Some special targets are placed on the tunnel vault and their coordinates are measured by means of a small photogrammetric block made up of four images. A wire is used to setup the scale and to make all measurements comparable overtime. The second method can be applied for the measurement of vertical deformations along the longitudinal profile of tunnels. A new image-based approach called ‘photogrammetric levelling’ is discussed here, which is based on the metric rectification of each single image depicting a couple of special rods to be hung on levelling benchmarks. This technique can be used to replace traditional optical and digital level instruments. Both applications can be carried out by using a calibrated amateur camera. Some experiments in controlled and real environments allowed assessing performances and limitations of these techniques for operational surveys in tunnel monitoring.  相似文献   

17.
可靠地监测基础设施的形变对于评估其结构健康至关重要。本文以中川国际机场为研究区,基于46景升轨和45景降轨Sentinel-1A雷达影像,使用SBASInSAR和PSInSAR技术获取了中川国际机场2017年3月27日至2020年3月23日、2017年3月20日至2020年3月28日的地表形变速率以及时序位移量,并采用内、外部检验的方式对4种监测结果进行了评定。同时结合相干性系数均值、直方图统计、形变速率方差及其标准差,选取最理想的形变结果从人为因素和自然因素分析了中川国际机场地表形变的成因。结果表明:4种形变结果总体较为一致,不同轨道模式数据采用同种时序InSAR技术所得监测点的方差和标准差较为接近,同种轨道模式数据采用不同时序InSAR技术的形变结果略有差异,SBASInSAR相比PSInSAR的监测结果更为稳健。中川国际机场存有零散的沉降区,机场西南角的形变最显著,最大的垂直沉降速率达11 mm·a-1。中川国际机场的地表形变与道路网、内部扩建等人为因素有关,地层界线与机场内部形变不直接相关,地表沉降区与岩性关联紧密。在进一步推进中川国际机场建设的同时,应避免过度人为活动带来的消极影响。研究结果以期为中川国际机场的土地利用规划以及灾害防治提供指导意见与相关信息。  相似文献   

18.
刘艳华  赵争  黄国满 《地学前缘》2006,13(3):104-107
合成孔径雷达干涉测量(InSAR)技术是传统的合成孔径雷达技术和射电天文学中的干涉测量技术相结合而发展起来的一项新的遥感技术,这一新技术以其在大范围地表高程测量和地表变形测量方面所具有的独特优势和巨大潜力,而成为对地测量和地学科学研究的一个重要的工具。同星载InSAR相比,机载InSAR在高分辨率区域测图方面具有较大的优势,而且数据采集的时间安排及飞行方位选取方面相对较灵活。而且SAR是一种主动微波遥感技术,具有全天时全天候的工作特征,这一技术也正在成为中国西部困难地区测图的一个非常有效的工具。在详细分析应用机载InSAR数据测量地表高程的基本原理的基础上,提出了机载InSAR自动生成DEM的技术流程,并以内蒙古丰镇地区的机载InSAR数据为基础进行了试验研究,取得了较好的效果,为这一新技术的进一步实际应用奠定了基础。  相似文献   

19.
The focus of this study is investigation of land subsidence in Semarang city Indonesia with the use of Interferometry Synthetic Aperture Radar (InSAR) of ALOS–PALSAR satellite. We processed 22 ascending SAR images during January 2007 to January 2009 plus two descending SAR images acquired on 6 June 2006 and 17 June 2007. The time series analysis of interferometry was performed by using 12 pairs of interferogram relative to 21 January 2007 and 8 pairs of interferogram relative 24 January 2008. The topographic phase contribution was removed using the 3-arcsec (90 m) Shuttle Radar Topography Mission (SRTM), Digital Elevation Model (DEM). We performed precision baseline estimation to vanish the fringes from baseline effect between master and slave data. In order to investigate the contribution of horizontal movement in our analysis, we constructed two interferograms of ascending orbit and descending orbit. The time series results exhibited that the area is subsiding continuously without a significant seasonal effect during January 2007 to January 2009. The land subsidence observed from InSAR data is approximately up to 8 cm/year. Three cross sections on image displacement show the extreme land subsidence occurred especially along the coastal area and lowland area where this area is considered as industrial with high-density settlements, consuming a lot of groundwater, and land is changed from agriculture and cultivation purposes to industrial estates and house. Our result also shows a consistency with historical pattern of subsidence measured by leveling data. The results highlight the potential use of InSAR measurements to provide better constraints for land subsidence in Semarang city Indonesia.  相似文献   

20.
The development of satellite technology is rapidly increasing the evolution of remote sensing. Satellite images give extensive useful information about the land structure that is easily manageable in the process of generating true, high-speed information which allows the forecasting of future environmental and urban planning. Remote sensing comprises active and passive systems. Passive sensors detect natural radiation that is emitted or reflected by the object or surrounding area being observed. Active systems which produce their own electromagnetic energy and their main properties are their ability of collecting data in nearly all atmospheric conditions, day or night. These systems are frequently used to generate a digital elevation model (DEM) because they cover large areas. DEM supplies essential data for applications that are concerned with the Earth’s surface and DEMs derived from survey data are accurate but very expensive and time consuming to create. However, the use of satellite remote sensing to provide images to generate a DEM is considered to be an efficient method of obtaining data. Interferometric Synthetic Aperture Radar (InSAR) is a new geodetic technique for determining earth topography. InSAR measurements are highly dense and they only give information in Line of Sight of Radar. In the study, interferograms were produced from the InSAR images taken by ERS satellites in 1992 and 2007 and we developed the methods to generate a DEM using the InSAR technique and present the results relating to Kayseri Province in Turkey. The accuracy of the DEM derived from the InSAR technique is evaluated in comparison with a reference DEM generated from contours in a topographical map.  相似文献   

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