利用DInSAR和GPS综合方法估计地表3维形变速率

在分析基于贝叶斯统计和马尔科夫随机场理论的解析优化法的基础上,提出以GPS提供的高精度的水平形变速率作为约束,利用直接分解法,将DInSAR的斜距向形变速率分解成垂直形变速率。试验结果表明,直接分解法有效地综合了GPS的高水平精度与DInSAR的高垂直精度优点,且计算简单,克服了解析优化法可能出现的数值不稳定问题。     

基于DInSAR技术与WorldView-2影像的煤矿塌陷区信息提取研究

结合DIn SAR与World View-2光学遥感解译技术,对研究区进行多源数据处理,提取研究地区的煤矿塌陷区信息,然后对处理后的两种结果进行对比。二者既有区别,又可以互补,最终在研究区形成完整的塌陷区信息。     

基于ALOS PALSAR数据进行雷达差分干涉提取玉树地震同震地表形变场

本文针对2010年4月14日玉树地震引起的地表形变,使用日本ALOS卫星PALSAR L波段雷达影像数据,应用两轨雷达差分干涉(DInSAR)处理得到了以玉树为中心11 000km2范围内的同震形变场,空间分辨率为8m,并在此基础上对玉树地震的震源机制和发震机理进行了分析。研究结果表明L波段雷达数据适合在地形起伏较大的地区进行DInSAR形变探测。该同震形变场信息可为玉树地震的同震形变反演提供参考数据。该研究进一步证实DInSAR技术在大规模地表形变探测和地学研究领域具有广阔的应用前景。     

Review on InSAR based displacement monitoring of Indian Himalayas: issues,challenges and possible advanced alternatives

Natural and man-made disasters like earthquakes, landslides, avalanches, unplanned mining are some of the most serious factors responsible for earth surface displacement. These incidences can be harmful for the society due to loss of life and also threatful for future urban development. Therefore, continuous monitoring of disasters in terms of displacements is of fundamental importance in a modern well-organized society to understand its effects on the social and economic fabric. Availability of SAR data has been proved to be an excellent source for estimation of surface displacements with high accuracies. However, in India, SAR interferometry-related displacement measurement has still not gained appreciable momentum. More rigorous research needs to be carried out for the efficient use of this new generation technique. This review article is an attempt to discuss the issues related to SAR-based displacement studies so far conducted on Indian Himalayan region and possible advanced alternatives.     

台湾浊水溪冲积扇地表变形监测雷达干涉技术与资料融合方法

浊水溪冲积扇为台湾目前最严重的地层下陷区,已设置包括DInSAR、GPS、水准测量、磁环分层式监测井与地下水位井等多元监测系统。大范围监测地层下陷方法中的水准测量有取样性不足之缺点,而DInSAR也易受相位不相关与大气误差影响而致精度降低。本研究利用2006~2008年期间共20幅ENVISAT卫星影像,搭配PSI技术,有效降低DInSAR的误差影响,同时获得107.6像素/km2的取样密度,弥补了水准测量取样密度仅0.2个/km2的取样性不足,透过295个监测点交叉验证,PSI与水准测量的成果显示两者的均方根误差为0.6cm。本研究亦发展了资料融合方法,有效结合水准测量与PSI成果,实验结果显示融合后的成果更能精确展现下陷的范围与下陷中心的变化,同时该成果与水准测量之均方根误差降至0.4cm。     

矿区地表沉陷D-InSAR监测分析与应用

针对常规矿区地表沉陷监测方法的缺点,基于D-InSAR技术,对2016年12月18日—2017年2月25日的两景RADARSAT-2雷达数据进行差分干涉处理,获取了研究区域监测时间段内的开采沉陷信息,监测到3处沉陷盆地分布,结合实际情况,对监测结果和精度进行了分析。结果表明,D-InSAR技术能够有效监测矿区的地表沉陷分布及特征,可为研究大范围矿区的地表沉陷动态监测提供技术参考。     

联合DInSAR与Offset-tracking技术监测高强度采区开采沉陷的方法

高强度煤炭开采产生巨大的地表形变,形变相位梯度过大导致干涉测量解缠错误,单一采用常规DInSAR及其衍生技术都无法获得地表沉陷主值。本文提出一种新的解决方案,即联合利用DInSAR与偏移量追踪技术（Offset-tracking）各自的技术优势,实现开采区大变形的准确提取,并基于GAUSS函数模型拟合恢复沉陷区剖面形态。基于2012年2月13日和2012年11月27日两景高分辨率SAR数据（RADARSAT-2,5 m精细波束模式（MF5））为数据源,以神东矿区布尔台矿、寸草塔一矿、二矿为研究区,采用常规DInSAR技术获得亚厘米级沉陷区边界,边界沉陷值处于-0.01~ -0.02 m;利用偏移量追踪方法获取米级地表沉陷中心主值,中心沉陷值集中在-1.0~ -4.0 m。将2种方法监测到沉陷信息分段融合,最后采用GAUSS函数模型重构矿区开采沉陷下沉特征曲线。结果表明,偏移量追踪方法可弥补DInSAR技术监测大量级形变信息的不足,联合技术可完整获取高强度采区的大形变沉陷。     

Polarimetric differential SAR interferometry in an arid natural environment

Ground deformation measurements have contributed to a better understanding of the processes and mechanisms involved in natural hazards. Those include landslides, subsidence, earthquakes and volcanic eruptions. Spaceborne Differential Interferometric Synthetic Aperture RADAR (DInSAR) is a well studied technique for measuring ground deformation. Quality of deformation measurements, however, is often degraded by decorrelation. With the advent of fully polarimetric SAR satellite sensors, polarimetric optimization techniques exploiting polarimetric diversity improve the phase quality of interferograms. In this paper, we analyzed three polarimetric optimization methods to determine the optimal one for application in an arid natural environment. We considered coherence decomposition in single and double phase center scenarios. Coherence estimation bias associated with each optimization method has been analyzed. We compared the derived displacement values with terrestrial GPS measurements. The study shows that polarimetric optimization increases the number of coherent pixels by upto 6.89% as compared with a single polarization channel. The study concludes that polarimetric optimization coupled with DInSAR analysis yields more reliable deformation results in a low coherence region.     

Monitoring land motion due to natural gas extraction: Validation of the Intermittent SBAS (ISBAS) DInSAR algorithm over gas fields of North Holland,the Netherlands

The differential interferometric synthetic aperture radar (DInSAR) remote sensing technique has proven to be invaluable in the remote monitoring of earth surface movements associated with the extraction and geostorage (subsurface injection) of natural resources (water, oil, gas). However, a significant limitation of this technique is the low density and uneven coverage that may be achieved over vegetated rural environments. The Intermittent Small Baseline Subset (ISBAS) method, an amended version of the established SBAS algorithm, has been designed to improve coverage over rural, vegetated, land cover classes by allowing for the intermittent coherence that is predominant in such areas. In this paper we perform a validation of the ISBAS method over an area of gas production and geostorage in North Holland, the Netherlands. Forty-two ERS-2 (SAR) C-band images (1995–2000) and 63 ENVISAT (ASAR) C-band images (2003–2010) were processed using the ISBAS technique and the derived measurements enabled the identification of subsidence patterns in rural and urban areas alike. The dominant feature was an area of subsidence to the west of Alkmaar, attributed to natural gas production from the Bergermeer reservoir, where subsidence rates in the region of 3 mm/year were measured. Displacements derived using linear and non-linear surface deformation models were validated with respect to the first order system of levelling benchmarks which form the Amsterdam Ordnance Datum (NAP). It was established that ISBAS products were accurate to within 1.52 mm/year and 1.12 mm/year for the ERS and ENVISAT data sets respectively. Errors achieved were comparable to results using persistent scatterers interferometry (PSI) during a validation activity carried out in the European Space Agency Terrafirma project. These results confirm the capability of the ISBAS method to provide a more regular sampling of land motion measurements over gas fields that may be critically used in future to infer the properties of buried, fluid-filled, porous rock.