ENVI SARscape高级雷达数据处理工具

合成孔径雷达（SAR）拥有独特的技术魅力和优势,逐渐成为国际上的研究热点之一,其应用领域越来越广泛。SAR数据可以全天候对研究区域进行量测、分析以及获取目标信息。InSAR技术可提取地形信息和地表形变信息,SAR及其干涉测量技术主要应用于地形数据（DEM）提取、地表沉降监测、滑坡／冰川移动监测、目标识别与跟踪、原油泄漏...     

ENVI SARscape高级雷达数据处理工具

合成孔径雷达（SAR）拥有独特的技术魅力和优势,渐成为国际上的研究热点之一,其应用领域越来越广泛。SAR数据可以全天候对研究区域进行量测、分析以及获取目标信息。InSAR技术可提取地形信息和地表形变信息,SAR及其干涉测量技术主要应用于地形数据（DEM）提取、地表沉降监测、滑坡／冰川移动监测、目标识别与跟踪、原油泄漏跟踪、作物生长跟踪、农作物产量评估、森林制图,以及洪水、火灾和地震的灾害评估等领域。     

永久散射体雷达干涉研究综述

传统D\|InSAR技术虽然在地表形变测量应用中得到广泛应用,但其测量精度容易受失相干、大气效应、DEM误差等的影响,测量结果有时甚至不可靠。为了突破这些限制,在D\|InSAR技术中引入时间维,筛选出时序SAR图像上受失相干影响较小的像元,建立并解算相位模型,从而提取形变信息。PS\|InSAR技术自出现以来,经过不断改进,在受失相干影响较大的长期缓慢形变监测中发挥了重要作用,一直是近年来雷达干涉领域研究的重点问题。详细梳理了PS\|InSAR技术的发展历史,总结了关键技术环节的改进算法以及应用领域,指出现有PS\|InSAR技术仍然存在的问题以及可能的发展趋势。     

基于SARscape的干涉叠加在地表形变监测中的应用

地表形变主要表现为地震形变、地面沉降、山体滑坡等,由InSAR技术发展而来的干涉叠加通过挖掘时间序列SAR图像获取mm级的形变信息。本文介绍了干涉叠加技术的基本原理和技术流程、基于永久散射体的方法,利用2008年～2010年的23幅Cosmo-skymed数据对北京奥林匹克公园内的主要区域进行了地表形变的监测。     

北京城区地表沉降监测与时空演化特征分析

地表沉降是我国平原地区的主要地质灾害,已经成为制约我国社会、经济可持续发展的重要灾种之一,是地理国情监测的重要监测内容之一。北京市作为我国首都,是拥有2000多万人口的特大型都市,城区人口密集,地下交通与市政管网发达,是重要的全国铁路公路交通枢纽,因此积极开展该地区地表沉降监测的研究与应用对城市的发展与安全具有重大意义。该文应用合成孔径雷达差分干涉测量DInSAR新技术之一的短基线集法,获取北京城区地表沉降的范围、时间序列累积沉降量和年平均形变速率等信息,针对监测结果进行了形变中心时空演化特征、影响因素的分析,为城市规划制定、国土资源开发及大型工程建设等提供参考依据,为政府部门掌握区域地面沉降的空间分布及变化规律、制定科学有效的沉降防控措施具有重要意义。     

多模式雷达在矿区沉降监测中的应用研究

合成孔径雷达差分干涉测量(DInSAR)技术在地表形变监测方面已得到广泛应用。介绍了将差分InSAR技术运用于矿区地表沉降监测,获得了河北峰峰煤矿地表Envisat/ASAR和ALOS/PALSAR的雷达形变干涉相位图,并对Envisat C波段和ALOS L波段的形变干涉相位图进行了相干特性和相位特性的分析。通过综合考虑C波段和L波段的优势与不足,将两者联合使用,实验表明利用多模式雷达数据对矿区地表沉降进行检测的可行性。同时,通过对雷达干涉相位图的分析,能够及时提供正在进行地下开采活动的矿区地理位置。     

重轨星载InSAR测量中的大气校正方法综述

随着合成孔径雷达干涉测量(Interferometric Synthetic Aperture Radar,InSAR)技术在地形测绘及地表形变监测等领域应用日益广泛,提高其测量精度成为该技术领域近期研究的热点之一。而InSAR测量过程中的大气效应是限制其测量精度提高的主要误差源之一,如何经济有效地消除大气效应引起的延迟位相(即大气校正)是InSAR技术应用中亟待解决的问题。详细介绍了InSAR测量中现有的大气校正方法,并评述了各自的优缺点及适用条件。最后对InSAR大气校正研究中仍就存在的问题进行了概括并提出展望。     

雷达InSAR数据在矿山地表形变监测中的应用研究

针对矿山地表形变这一特殊区域，开展星载InSAR测量的研究工作，在大量调研的基础上确定技术流程和关键技术及解决方法，选择具有典型意义的河北武安地区，应用InSAP数据，采用三次、二次过境差分法处理，获得了几个时间间隔内矿山开采地表形变图像。经与实际对比应用效果较好。真实地反映了地表形变的动态信息。实践证明，利用InSAR数据进行地表形变动态监测有着重要的现实意义和广泛的应用前景。     

面向地表形变高精度监测的GNSS-InSAR融合方法北大核心CSCD

GNSS-InSAR数据融合进行监测地表形变是目前地表形变监测领域研究的热点问题,传统GNSS-InSAR数据融合方法融合简单、不能动态地反映地表形变特点,导致数据使用不充分、形变特征精度低等后果。提出了一种新的基于InSAR校正值和卡尔曼滤波的GNSS-InSAR融合方法。根据时间序列的GNSS观测值和InSAR校正观测值的时空相关性,通过卡尔曼滤波对两种数据进行融合,得到更精确的地表三维形变结果。利用2018年11月15日至2022年6月3日103景Sentinel-1A数据和同期13个GNSS点位数据进行处理,实验结果表明:校正后的InSAR观测值与GNSS观测值经卡尔曼滤波融合结果比未校正的InSAR观测值与GNSS观测值融合结果精度高45%,比InSAR观测值精度高57%。因此,基于InSAR校正值和卡尔曼滤波的GNSS-InSAR融合模型提高了InSAR变形监测的精度,拓展提升InSAR应用范围的广度和深度。     

基于小基线InSAR技术监测九台营城矿区2012年地表形变

通过采用小基线InSAR技术,将离散的DInSAR观测连接起来,获取吉林省九台营城矿区线性地表形变量,通过去除大气延迟相位计算非线性形变量,进而获取时间上连续的沉降场。经实地调查验证,InSAR计算结果较好地吻合了矿区开采范围和地表建筑物破坏情况。最后分析了营城矿区2012年沉降的分布和地表形变随时间的变化情况,揭示矿区沉降漏斗的分布、发展和演化规律。     

Deformation mapping in three dimensions for underground mining using InSAR – Southern highland coalfield in New South Wales,Australia

This article presents 3D surface deformation mapping results derived from satellite synthetic aperture radar (SAR) data acquired over underground coal mines. Both ENVISAT Advanced Synthetic Aperture Radar (ASAR) and Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) data were used in this study. The quality of the 3D deformation mapping results due to underground mining is mainly limited by two factors. (1) Differential interferometric synthetic aperture radar (DInSAR) is less sensitive to displacement along the north–south direction in the case of the current SAR satellite configurations. (2) The mining-induced displacement is continuous and nonlinear; and the accuracy of the 3D DInSAR measurement is severely affected by the similar but non-identical temporal overlaps of the InSAR pairs. The simulation and real data analyzes have shown that it would be more practical to use DInSAR pairs with the assumption of negligible northing displacement to derive the displacements in the easting and vertical directions. The northing displacement could then be estimated from the residuals. This limitation could be overcome in the future with the launch of more radar satellites, which would provide better viewing geometry.     

The present status of subsiding land vulnerable to roof collapse in the Jharia Coalfield,India, as obtained from shorter temporal baseline C-band DInSAR by smaller spatial subset unwrapped phase profiling

In this paper, we identified recently subsiding areas in Jharia Coalfield, Jharkhand, India from the shorter temporal baseline Radarsat-2 C-band interferometric synthetic aperture radar (InSAR) data pairs of 2012. Although shorter wavelength C-band differential InSAR (DInSAR) is more sensitive to slow deformation and better suited for higher precision land subsidence measurement, the dynamic and adverse land cover in mining areas and resulting temporal decorrelation problem poses a serious problem for DInSAR observation in mining areas. We used smaller temporal baseline data pairs and adopted InSAR coherence-guided incremental filtering with smaller moving windows to highlight the deformation fringes over temporal decorrelation noise. We identified the deformation fringes and validated them based on ground information to prepare the land subsidence map of the coalfield in 2012. Several new, previously unreported subsidence areas were detected in the present study with a total subsiding area of 6.9 km². The recent incidence of roof collapse on 15 November 2014 at Angar Patra village in Katras region of the coalfield where 45 houses collapsed and 10 people were injured is situated in a highly subsiding vulnerable area as obtained from the present study. Due to spatial discontinuities of InSAR coherence, DInSAR phase unwrapping for the entire study area in one go did not appear feasible. To avoid this problem, we performed DInSAR processing in smaller spatial subsets and unwrapping of the subset interferograms by a ‘minimum cost flow’ algorithm. Subsequently, we plotted unwrapped phase profiles across the deformation fringes and retrieved the maximum deformation phase with respect to background phase and translated them into radar line of sight (LOS) displacement rates. For obtaining the average subsidence rates, we adopted InSAR coherence-weighted LOS displacement rates taking into account the contribution of each data pair as a function of DInSAR phase quality of the fringe areas. Ground-based subsidence measurements by precision levelling were conducted in four test sites that had been undergoing active underground mining during the observation period. We compared space-borne DInSAR-based subsidence rates obtained by the adopted technique with precision levelling measurements. Overall, the results are found to agree well. In the four test sites with gentle to flat topography, land subsidence occurs at slow to moderate rates due to compression of in-filled material (resulting from sand stowing in underground mining), without any evidence of roof collapse. In such cases, the horizontal displacement component is less significant, and overall surface displacement occurs essentially in the vertical direction. However, we assessed the nature of subtle horizontal strain to infer relative shrinkage or dilation of the land surface which could be additive or subtractive to vertical displacement in DInSAR-based LOS displacement.     

Monitoring of slow ground deformation by ERS radar interferometry on the Vauvert salt mine (France): Comparison with ground-based measurement

The differential SAR Interferometry (DInSAR) technique has been applied to a test site near Vauvert (France) to detect and monitor ground deformation. This site corresponds to the location of an industrial exploitation of underground salt using the solution mining technique. An area of subsidence has been observed using in situ measurements. Despite conditions unfavorable for InSAR because of the vegetal cover, we show that radar remote sensing observations provide valuable information which substantially improves our knowledge of the phenomenon. An adaptive phase filtering process has been used to improve the coherence level. In particular, our study shows that the geometry of the subsidence bowl is different to that previously assumed using ground-based techniques only. The size of the subsidence bowl (8 km) is larger than expected. This information will be useful for further modeling of the deformation and to improve the coverage of the in situ measurement networks. It also shows that radar interferometry can be used for the long-term monitoring of such sites and to predict potential environmental issues.     

Surface movements in Bologna (Po Plain — Italy) detected by multitemporal DInSAR

We studied the surface deformations affecting the southeastern sector of the Po Plain sedimentary basin, in particular the area of Bologna. To this aim an advanced DInSAR technique, referred to as DInSAR-SBAS (Small BAseline Subset), has been applied. This technique allows monitoring the temporal evolution of a deformation phenomenon, via the generation of mean deformation velocity maps and displacement time series from a data set of acquired SAR images. In particular, we have processed a set of SAR data acquired by the European Remote Sensing Satellite (ERS) sensors and compared the achieved results with optical levelling measurements, assumed as reference. The surface displacements detected by DInSAR SBAS from 1992 to 2000 are between 10 mm/year in the historical part of Bologna town, and up to 59 mm/year in the NE industrial and agricultural areas. Former measurements from optical levelling referred to 1897 show 2-3 mm/year vertical movements. This trend of displacement increased in the second half of the 20th century and the subsidence rate reached 60 mm/year. We compared the more recent levelling campaigns (in 1992 and late 1999) and DInSAR results from 1992 to 1999. The standard deviation of the difference between levelling data, projected onto the satellite Line Of Sight, and DInSAR results is 2 mm/year. This highlights a good agreement between the measurements provided by two different techniques. The explanation of soil movements based on interferometric results, ground data and geological observations, allowed confirming the anthropogenic cause (surface effect due to the overexploitation of the aquifers) and highlights a natural, tectonic, subsidence.     

Land deformation monitoring using coherent target-neighbourhood networking method combined with polarimetric information: a case study of Shanghai,China

In this article, an advanced approach for land deformation monitoring using synthetic aperture radar (SAR) interferometry combined with polarimetric information is presented. The linear and nonlinear components of the deformation, the error of the digital elevation model (DEM) and the atmospheric artefacts can be achieved by a coherent target (CT)-neighbourhood networking approach. In order to detect recent land deformation in Shanghai, China, 12 ENVISAT advanced synthetic aperture radar (ASAR) alternating polarization images acquired from January 2006 to August 2008 are employed for deformation analysis. Over a 2.5-year period, two deformation velocity fields from HH and VV modes over Shanghai are derived using the CT-neighbourhood networking SAR interferometry (InSAR), then integrated into a final deformation map by a fusion scheme. It is found that the annual subsidence rates in the study area range from??20 to 10 mm year^?1 and the average subsidence rate in the downtown area reaches??7.5 mm year^?1, which is consistent with the local government statistics published in 2007.     

COSMO-SkyMed数据在常州市地表形变监测中的应用

小基线集合成孔径雷达干涉测量技术(SBAS-InSAR)已成功应用于城市地表形变监测,并表现出极大的潜力和优势。X波段高分辨率雷达卫星在地表微小形变探测方面较C波段和L波段更为敏感。选取覆盖常州地区COSMO-SkyMed高分辨率SAR影像,采用SBAS-InSAR方法获得了地表形变时间序列,对比水准观测数据,分析了干涉测量结果的精度,根据历史地下水位监测数据,分析了地下水水位变化对地表形变的影响。结果表明:干涉测量结果与水准观测数据具有很好的一致性,沉降区域主要发生在武进区,最大沉降量超过-40mm,主城区出现了轻微的回弹现象,回弹达到+5mm;地下水水位持续上升与地面沉降减缓、地面回弹趋势一致,地下水水位变化仍然是常州市地表形变的主要影响因素。     

基于SBAS-InSAR技术的煤矿开采沉陷监测与分析

地下煤炭资源大量开采导致的地表形变,引发严重的安全和环境隐患,雷达干涉测量技术是高精度、大范围地表形变监测的重要手段之一。以辽宁省沈阳市沈北新区蒲河煤矿为例,采用SBAS-InSAR技术探测2018—2019年矿区地表形变结果,获取了采煤引起地表形变的时空分布特征,结合采场所在区域的地质条件和变形诱发因素,利用数值模拟技术对观测形变结果进行模拟分析,进而讨论了蒲河煤矿地面沉降在时间和空间上的变形规律和机制。InSAR形变监测结果显示,开采区域内存在两处沉降漏斗,且数值模拟结果与InSAR形变观测值分布规律一致,反演结果接近实际情况,可为相关部门制定地面沉降防治措施提供科学依据。