INSAR技术在海州露天矿边坡变形监测中的应用研究

露天矿边坡的变形监测一直是矿山安全生产的重要工作,运用合成孔径雷达干涉(INSAR)测量技术对边坡进行监测是近年来微波遥感研究的一个重要方向。本文分析了INSAR技术在边坡变形监测中的技术优势及研究的进展情况,并利用海州露天矿传统监测实测数据和INSAR监测进行比较,结果表明,INSAR技术可以实现对大型露天矿边坡有效地监测,具有一定的技术优势和广阔的应用前景。     

Remarks on correcting ionospheric distortions in L-band radar interferometry

The L-band synthetic aperture radar (SAR) interferometry (InSAR) technique has a lower accuracy due to ionospheric phase distortions. Recently, a multiple-aperture interferometry (MAI)-based ionospheric correction method has been proposed. Using four types of ionosphere-distorted interferograms, the performance of the correction method was evaluated and then analyzed the feasibility of the correction method. The test interferograms contained severe azimuth streaking, low-frequency ionospheric phase distortion and drastic phase change due to the ionosphere. The results showed that (i) the existence and magnitude of ionospheric phase distortions can be recognized from MAI interferograms and (ii) the MAI-based ionospheric correction method efficiently reduced severe azimuth streaking and low-frequency distortion but did not mitigate the drastic phase change perfectly. It is allowed (i) to determine whether a given SAR interferogram has an ionospheric distortion and (ii) to predict whether the ionospheric distortion can be corrected by using the MAI-based ionospheric correction method.     

Satellite interferometric data for landslide intensity evaluation in mountainous regions

Multi-Temporal Interferometric Synthetic Aperture Radar (MTInSAR) data offer a valuable support to landslide mapping and to landslide activity estimation in mountain environments, where in situ measures are sometimes difficult to gather. Nowadays, the interferometric approach is more and more used for wide-areas analysis, providing useful information for risk management actors but at the same time requiring a lot of efforts to correctly interpret what satellite data are telling us. In this context, hot-spot-like analyses that select and highlight the fastest moving areas in a region of interest, are a good operative solution for reducing the time needed to inspect a whole interferometric dataset composed by thousands or millions of points. In this work, we go beyond the concept of MTInSAR data as simple mapping tools by proposing an approach whose final goal is the quantification of the potential loss experienced by an element at risk hit by a potential landslide. To do so, it is mandatory to evaluate landslide intensity. Here, we estimate intensity using Active Deformation Areas (ADA) extracted from Sentinel-1 MTInSAR data. Depending on the localization of each ADA with respect to the urban areas, intensity is derived in two different ways. Once exposure and vulnerability of the elements at risk are estimated, the potential loss due to a landslide of a given intensity is calculated. We tested our methodology in the Eastern Valle d’Aosta (north-western Italy), along four lateral valleys of the Dora Baltea Valley. This territory is characterized by steep slopes and by numerous active and dormant landslides. The goal of this work is to develop a regional scale methodology based on satellite radar interferometry to assess the potential impact of landslides on the urban fabric.     

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利用时序PS-InSAR监测青藏高原冻土区地表形变

多年冻土及其活动层的变化对研究全球气候变化和生物多样性具有重要意义.传统的冻土测量方法通常只针对特定地点,空间覆盖范围有限,尤其是青藏高原冻土.本文采用C波段Sentinel-1A IW模式数据并结合一种顾及永久散射体的小基线SAR干涉(SBAS)技术,对青藏高原沱沱河地区地面形变和冻融过程进行了研究.探测到的地面位移...     

TanDEM-X multiparametric data features in sea ice classification over the Baltic sea

In this study, we assess the potential of X-band Interferometric Synthetic Aperture Radar imagery for automated classification of sea ice over the Baltic Sea. A bistatic SAR scene acquired by the TanDEM-X mission over the Bothnian Bay in March of 2012 was used in the analysis. Backscatter intensity, interferometric coherence magnitude, and interferometric phase have been used as informative features in several classification experiments. Various combinations of classification features were evaluated using Maximum likelihood (ML), Random Forests (RF) and Support Vector Machine (SVM) classifiers to achieve the best possible discrimination between open water and several sea ice types (undeformed ice, ridged ice, moderately deformed ice, brash ice, thick level ice, and new ice). Adding interferometric phase and coherence-magnitude to backscatter-intensity resulted in improved overall classification per- formance compared to using only backscatter-intensity. The RF algorithm appeared to be slightly superior to SVM and ML due to higher overall accuracies, however, at the expense of somewhat longer processing time. The best overall accuracy (OA) for three methodologies were achieved using combination of all tested features were 71.56, 72.93, and 72.91％ for ML, RF and SVM classifiers, respectively. Compared to OAs of 62.28, 66.51, and 63.05％ using only backscatter intensity, this indicates strong benefit of SAR interferometry in discriminating different types of sea ice. In contrast to several earlier studies, we were particularly able to successfully discriminate open water and new ice classes.     

地球卫星VLBI观测研究进展

随着地球卫星在资源、导航定位、授时、跟踪以及数据中继等经济和军事领域的作用不断增强,传统的测距测速技术已无法满足对卫星定位精度的实际需求。由于VLBI技术具有高精度角分辨率的特点,人们尝试将其应用于人造地球卫星的观测。针对卫星VLBI观测方面,首先介绍了卫星VLBI观测技术的基本原理及其与传统河外射电源VLBI观测的差异,然后介绍了中外学者应用VLBI技术进行地球卫星观测的研究进展及相关成果,最后对以往近地卫星VLBI观测研究存在的问题进行总结,并讨论了目前以及将来可能的解决方案。     

基于二维形变场的地基SAR精度验证与分析

地基SAR(synthetic aperture radar)可实现高精度的小区域性连续形变监测。为研究其形变探测能力与精度,建立了一套精度验证平台和系统。在楼顶布设不同位置分布的角反射器,并采用步进平台控制角反射器模拟不同数值形变,形变角反射器与稳定点及楼顶表面构成小区域二维形变场,利用IBIS-L(image by interferometric system-landslides)系统完成形变监测与分析。实验结果表明,当角反射器发生毫米级形变时,地基干涉雷达IBIS-L系统形变探测平均精度为0.27 mm,而角反射器发生亚毫米级形变时,其形变探测平均精度为0.11 mm;该系统可以实现小区域性的亚毫米级形变探测,对于缓慢微小变化,其具有更好的形变探测能力与可靠性。     

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利用Sentinel-1A数据、D-InSAR和沿轨干涉技术获取2016年高雄MS6.7地震三维形变场

提出一种沿轨干涉技术来获取Sentinel-1A数据中burst重叠区域内的方位向形变,进而通过内插方法得到非重叠区的方位向形变。针对D-InSAR的雷达视线向形变与沿轨干涉的方位向形变精度差异,采用基于加权最小二乘的方法解算了2016年高雄MS6.7地震的三维形变场。结果表明,高雄地震的同震形变以垂直和东西方向形变为主,且形变主要分布在断层左右两瓣。左瓣抬升,最大达到12 cm;右瓣下沉,最大达到8 cm;左右两瓣均伴随着向西的位移,最大达6 cm。在左右两瓣之间,该地震还具有西北-东南走向的断层特性。