2005珠峰GPS测量大地高确定

珠峰大地高确定是计算珠峰海拔高程一个关键环节。2005珠峰GPS测量大地高确定主要包括青藏地区GPS监测网、珠峰地区GPS控制网和珠峰峰顶GPS联测三部分;并利用GPS峰顶联测数据直接计算大地高。本文结合珠峰峰顶GPS观测自然环境恶劣的特点,分析比较了各种计算方案,确定了一种较为合理的解算珠峰大地高的GPS数据处理方法,获得了较为满意的珠峰大地高计算结果。     

利用GPS监测地面沉降的精度分析

为了监测天津地区的地面沉降,配合精密水准测量,1995年布设了一个GPS监测网,每年的10-11月进行一次精密GPS测量,并与同期进行的精密水准复测的垂直形变结果进行比较研究。根据1995-2004连续十年GPS大地高与精密水准测量观测数据对比研究,验证了GPS监测地面沉降的精度,从理论和实践上论证了GPS大地高变化完全可以像精密水准测量一样高精度获取水准测量点的沉降值,从而得出在地面沉降监测中GPS测量可用于监测地面沉降的结论。     

InSAR技术在沂沭断裂带地表形变监测中的应用研究

针对常规大地测量监测沂沭断裂带地表形变结果无法全面反演该区域构造应力场的局限性,尝试采用PS和SBAS两种In SAR时序分析技术对该区域地表形变进行监测。首先对SBAS-In SAR技术的原理进行详细推导和分析;在此基础上,对覆盖研究区的14景ENVISAT-ASAR数据采用PS-In SAR和SBAS-InSAR技术进行处理,分别提取了该区域地表年平均形变速率图;通过与水准监测数据的对比分析发现:InSAR时序分析方法在大范围、持续缓慢断裂带地表形变监测中能够获取与精密水准监测一致的形变趋势,且SBAS-In SAR技术在数据量较少情况下能获得更好的监测效果。这表明In SAR时序分析技术可以作为断裂带微小地表形变监测的有效手段。     

Hybrid conventional and Persistent Scatterer SAR interferometry for land subsidence monitoring in the Tehran Basin,Iran

Excessive groundwater extraction has caused land subsidence in a large rural area located southwest of Tehran, Iran. We used radar images to estimate the temporal and spatial variation in the magnitude of the subsidence. Due to the large perpendicular baselines and rapid temporal decorrelation of the available data, the application of conventional synthetic aperture radar interferometry (InSAR) to monitor the deformation was not possible. Instead, we applied a recently developed Persistent Scatterer InSAR (PSI) method but found that displacements were underestimated in some areas due to high deformation rates that cause temporal aliasing of the signal. We therefore developed a method that combines conventional InSAR and PSI to estimate the high deformation rates in the southwestern Tehran Basin. We used rates estimated from conventional small temporal baseline interferograms to reduce the likelihood of aliasing and then applied PSI to the residual phase. The method was applied to descending and ascending ENVISAT ASAR images spanning from 2003 to 2009. Mean line-of-sight velocities obtained from both orientations that were further decomposed into horizontal and vertical deformation components were highly compatible with each other, indicating the high performance of the applied method. The mean precision of the estimated vertical component is 2.5 mm/yr. We validated our results using measurements from a continuous GPS station located in one of the subsiding areas. The results also compare favourably with levelling data acquired over a different time interval. Finally, we compared the estimated displacements to hydraulic head variations and geologic profiles at several piezometric wells. We found that the geology is the most important factor controlling the subsidence rate in the southwestern Tehran Basin, regardless of the water level decline.     

Ground deformation associated with post-mining activity at the French–German border revealed by novel InSAR time series method

We present a novel methodology for integration of multiple InSAR data sets for computation of two dimensional time series of ground deformation. The proposed approach allows combination of SAR data acquired with different acquisition parameters, temporal and spatial sampling and resolution, wavelength and polarization. Produced time series have combined coverage, improved temporal resolution and lower noise level. We apply this methodology for mapping coal mining related ground subsidence and uplift in the Greater Region of Luxembourg along the French–German border. For this we processed 167 Synthetic Aperture Radar ERS-1/2 and ENVISAT images acquired between 1995 and 2009 from one ascending (track 29) and one descending (track 337) tracks and created over five hundred interferograms that were used for time series analysis. Derived vertical and east–west linear deformation rates show with remarkable precision a region of localized ground deformation located above and caused by mining and post-mining activities. Time series of ground deformation display temporal variability: reversal from subsidence to uplift and acceleration of subsidence in the vertical component, and horizontal motion toward the center of the subsidence on the east–west component. InSAR results are validated by leveling measurements collected by the French Geological Survey (BRGM) during 2006–2008. We determined that deformation rate changes are mainly caused by water level variations in the mines. Due to higher temporal and spatial resolution the proposed space-borne method detected a larger number of subsidence and uplift areas in comparison to leveling measurements restricted to annual monitoring of benchmark points along roads. We also identified one deformation region that is not precisely located above the mining sites. Comparison of InSAR measurements with the water levels measured in the mining pits suggest that part of the water that filled the galleries after termination of the dewatering systems may come from this region. Providing that enough SAR data is available, this method opens new opportunities for detecting and locating man-made and natural ground deformation signals with high temporal resolution and precision.     

2005珠峰测高GPS测量及其数据处理

介绍了各种不同GPS测量的特点和数据处理方法，结合珠峰峰项GPS观测自然环境恶劣的特点，分析了各种计算方案，确定了一种合理的解算珠峰高程的GPS数据处理方案；取得了较为满意的计算结果。     

Validation and comparison of Advanced Differential Interferometry Techniques: Murcia metropolitan area case study

This paper is focused on the analysis of the performance of Stable Point Network (SPN) and Coherent Pixel Technique (CPT), which are Advanced Differential Interferometry Techniques (A-DInSAR) that estimate, among other results, mean deformation velocity maps of the ground surface and displacement time series from a SAR dataset. The test site is the metropolitan area of the city of Murcia (Spain) where a moderate slow subsidence induced by the overexploitation of aquifers is present. SAR data acquired between July 1995 and August 2005 from ERS and ENVISAT sensors have been processed by the SPN and CPT techniques and compared with in situ instrumental measurements assumed as reference. Experimental results have shown that both SPN and CPT techniques provide estimates of the deformation evolution in time with an absolute difference below 6 mm consistently in all comparisons: SPN vs extensometer, CPT vs extensometer and SPN vs CPT. The proposed validation and comparison experiment between both A-DInSAR techniques has been useful to observe their differences and complementarities.     

浅谈基于InSAR的南票煤矿开采沉陷区沉降量外业检核

经过时间序列InSAR技术处理后,得到监测时间段内南票区的地面形变平均速率、累计形变量、时间序列形变量,确定沉降区域。本文通过南票煤矿开采沉陷区基岩点、基本水准点、监测点布设以及这些点测量工作,提出山区采用水准测量和GPS测量联合方法,实现沉陷区沉降量核查。     

Geodetic Height Determination in 2005 Qomolangma Survey

Determining the geodetic height of Mount Qomolangma was one of the very important missions in the 2005 Qomolangma height survey. There were three GPS networks in the survey: regional GPS crustal deformation network, geodetic GPS control network, and GPS measurement on the mountain summit. Data collection and processing were introduced. The final data processing strategy and reasonable geodetic height were fairly determined based on careful data analysis.     

Land subsidence characteristics of Jakarta between 1997 and 2005, as estimated using GPS surveys

Jakarta is the capital city of Indonesia with a population of about 12 million people, inhabiting an area of about 625 km². It is well known that several areas in Jakarta are subsiding rapidly. There are four different types of land subsidence that can be expected to occur in the Jakarta basin, namely: subsidence due to groundwater extraction, subsidence induced by the load of constructions (i.e., settlement of high compressibility soil), subsidence caused by natural consolidation of alluvial soil and tectonic subsidence. In addition to the leveling method, Global Positioning System (GPS) survey methods have been used to study land subsidence in Jakarta. In this paper, we characterize subsidence in the Jakarta basin using eight episodic/campaign GPS surveys between 1997 and 2005. The estimated subsidence rates are 1–10 cm/year. The observed subsidence rates in several locations show a positive correlation with known abstraction volumes of groundwater extraction. These basin-wide series of GPS measurements show how this type of measurement can play an important role in multiple public policy decision making in this rapidly growing area.     

时序InSAR技术在地球环境监测及其资源管理中的应用:以交城-清徐地区为例

利用ALOS-1（2007-2010）、Sentinel-1A（2017-2018）存档数据对山西交城-清徐地区的地面沉降进行监测。结合小基线和永久散射体技术优点,在增加时间采样密度的基础上利用二维线性回归分析得到研究区域的形变速率和时间序列。经同期GPS观测结果校核表明:交城-清徐地区持续发生地面沉降,但山区和平原区域形变的空间分布、量级不同,引起形变原因也不同。平原地带沉降空间分布受构造断裂控制,断裂带两侧呈现明显的差异性形变,且最大沉降速率为－200 mm/a,沉降的主要原因是地下水超采,但经治理后地面沉降灾害有所缓解,表现为沉降速率小于－30 mm/a。山区主要由于矿产资源的长期开采,沉降中心不断向南移动,最大形变速率为－462 mm/a。     

GPS interactive time series analysis software

Time series analysis is an important part of geodetic and geodynamic studies, especially when continuous GPS observations are used to explore areas with a low rate of deformation. In this domain, having precise and robust tools for processing and analyzing position time series is a prerequisite. To meet this requirement, a new software package called GPS Interactive Time Series Analysis was developed using the MATLAB language. Along with calculating basic statistics and quality parameters such as mean and variance, the software is capable of importing and visualizing different time series formats, determining and removing jumps and outliers, interpolating data, and producing numerical and publication quality graphical outputs. Furthermore, bivariate statistical analysis (such as correlation coefficients, curvilinear and nonlinear regression), residual analysis, and spectral analysis (such as auto-spectrum, Lomb–Scargle spectrum, evolutionary power spectrum, and wavelet power spectrum) form the main analysis features of the software.     

永久散射体雷达差分干涉反演矿区时序沉降场

针对永久散射体差分干涉测量(PSIn SAR)算法流程,发展了基于周期函数模型的空间维解缠方法,并将其应用于矿区时间序列地表变形反演。通过在研究区域内安装人工角反射器(CR),将CR点上计算所得的周期模型参数分量作为整个网络的约束,通过空间约束平差以实现空间维解缠。选取了河南省境内白沙水库附近的煤矿密集区为主要研究区域,采用周期函数模型对矿区线性及非线性形变分量进行模拟,反演了2007年2月—2010年2月的时间序列形变场,并采用研究区域内的水准实测数据作为外部验证数据。实验结果表明:白沙水库周围区域存在着较为明显的沉降,在煤矿分布区域内累积最大沉降量超过了10 cm。沉降区域内以线性沉降趋势为主,非线性沉降较为缓慢,仅在水库的西南方向较为明显。应用已有的水准点实测形变值对实验结果进行验证分析,结果表明该方法精度可达约±2.1 mm,证实了本文采用的方法在矿区地表时序形变反演中的可行性和可靠性,对预防过度采矿导致的矿区塌陷具重要现实意义。     

Sentinel-1A数据的四川宜宾Ms6.0同震形变分析

为了获取2019年6月17日发生的四川宜宾Ms6.0地震引起的地表形变情况,该文利用欧空局宽幅模式的高分辨率新型Sentinel-1A卫星获取了此次地震的第一对同震干涉像对数据,使用D-InSAR技术获取宜宾市长宁县地区的同震形变场。结果显示,本次地震在震中西北方向分别形成了1个明显的沉降区和抬升区,在雷达视线方向上的最大沉降量为7.9 cm,最大抬升量为8.1 cm。通过与同一时间内的GPS高程测量形变量相比,D-InSAR解算的地表形变量与GPS监测点形变量基本一致,均不超过3 mm,表明了本文的D-InSAR形变解算结果的可靠性,体现了新型Sentinel-1A雷达卫星在地震形变监测领域有着很高的应用价值和潜力。     

基于 C 波段和 L 波段的 SBAS-InSAR 技术监测广州地面沉降

近10年来广州市频繁发生地面沉降、塌陷等地质灾害,造成巨大的生命财产损失,而且目前仍然在加剧。传统的监测技术如GPS、水准测量等难以开展大范围、高精度和高空间分辨率的地表沉降监测工作,而合成孔径雷达干涉测量技术(InSAR)正逐渐成为城市地表沉降监测的有效手段。文中采用短基线集(SBAS-InSAR)技术,通过17景ENVISAT/ASAR数据和21景ALOS/PALSAR数据,探测广州佛山地区2006—2011年的地表形变信息。将其与研究区内已有的水准测量数据进行比较,从而验证InSAR技术监测结果的可靠性。最后圈定了研究区的重点沉降区域并对沉降成因进行分析。     

IPTA方法在地面沉降监测中的应用

干涉点目标分析(IPTA)技术是一种新兴的In SAR形变测量技术。它克服了常规雷达差分干涉测量(DIn SAR)受失相干因素和大气延迟影响较大的问题。介绍了IPTA方法及处理流程,并对参数迭代估计、基线精化等关键问题进行了阐述。对加利福尼亚州安大略市的39幅ENVISAT ASAR数据进行IPTA处理,提取了2005—2010年间的地面沉降信息并进行了形变分析。结果表明,该方法在大范围地面沉降监测中应用效果良好。     

GPS高程拟合在矿区变形监测中的应用

利用GPS点水准联测数据,通过曲面拟合的方法得到高程异常值;最后通过对GPS拟合高程与水准测量高程的精度对比分析,论述了等级网GPS高程拟合在矿区地表变形监测中的可行性。     

多平台MC-SBAS长时序建模与形变提取方法

卫星时序差分雷达干涉已在区域地表形变监测中展现出极好的应用潜力,但因受卫星寿命及重访周期等因素的限制,单一卫星平台很难为长时间跨度(如5~10年)的时序形变计算与分析提供数据源。为扩展区域地表形变监测的时间跨度,本文提出了基于模型约束的短基线集(MC-SBAS)时序干涉方法,即使用非线性形变模型约束SBAS分析与处理,达到不同卫星平台数据融合和形变监测效率提高的目的。研究选取美国南加州地区为试验区域,使用2002—2005年获取的10幅ERS SAR影像和2004—2008年获取的20幅EnviSat ASAR影像,基于MC-SBAS提取该区域时序形变信息,时间跨度扩展为6.5年;以6个GPS站时序观测数据为参考,对MC-SBAS结果和常规SBAS结果进行了对比验证。分析表明,MC-SBAS、SBAS与GPS形变结果的均方根误差分别为8.7和11.7mm,MC-SBAS形变序列的连续性得到有效改善,而且形变监测精度得到提高。     

基于相干目标的干涉图叠加方法监测天津地区地面沉降

利用ENVISAT ASAR数据,采用基于相干目标的干涉图叠加方法,对天津地区的地面沉降现象进行了DInSAR监测试验.差分干涉处理采用"两轨法",使用校正了高程异常的SRTM DEM数据消除高程相位.以相干系数为标准选取了相干目标,解缠过程中运用了Delaunay三角剖分和权重最小费用流算法.本文获得的季度平均沉降速率图有效揭示了试验区地面沉降的空间展布及相对形变量,但其获得的绝对形变量尚需地面实测数据校验.     

利用GPS技术测定珠峰高程变化及其北坡地壳形变的初步分析

20世纪60年代以来，我国单独或与外国合作，在1966年、1975年、1992年、1998年、1999年和2005年对珠穆朗玛峰（以下简称珠峰）的高程及其北坡的地壳运动进行了6次大规模的大地测量，其中包括天文、重力、平面、高程和大气折射等方面的外业作业、数据处理和科学研究。本文对我国上述几次测量中的GPS和水准测量等数据进行了综合，对珠峰峰顶雪面高程值的变化和该地区地壳的水平运动和垂直运动进行了撂索。根据1992年和2005年的GPS测量，珠峰峰项雪面高程的变化在13a闻约下降25cm，平均年下降率为1．8cm。根据1992-2005年间的三次GPS测量，珠峰北坡地区的地壳水平运动平均每年以4cm的速度向北东45。方向推进。根据1966-2005年的多期水准测量，该地区的地壳垂直运动平均每年上升1.8mm。此外，若从以上各个时间段作进一步分析，则发现珠峰北坡地壳的水平运动和垂直运动在时间上和空间上都存在非平稳性。