GPS单历元定位新算法用于滑坡监测di

在滑坡变形较大时，常规GPS静态观测方式满足不了滑坡实时监测的需要. 本文结合滑坡变形的特点，利用GPS单历元定位新方法frac34;单历元阻尼LAMBDA方法，对滑坡实时形变进行了监测试验. 该方法不需要考虑GPS载波相位测量中棘手的周跳问题，每一历元即可搜索到正确的整周模糊度，从而获得监测点厘米级精度的坐标. 采用平滑方法后可以分辨出毫米级精度的坐标和滑动速度，扩大了GPS形变监测的应用范围. 本文简要介绍了新方法的原理，并使用低价位的单频GPS接收机，在江西省一个实测滑坡中取得了较好的应用效果.       

利用GPS技术监测大坝表面变形

目前GPS技术已能够提供连续、实时、无障碍和自动化服务,被广泛应用于各类变形监测。本文探讨GPS技术在大坝变形监测中的应用,以某水库大坝为例,介绍水库大坝变形监测GPS点布设及观测要求,并提出GPS观测整体方案,通过案例介绍大坝变形监测点布设及数据处理流程,简单分析大坝变形及影响因素。     

丹巴县甲居滑坡GPS地表监测阶段成果

本文主要介绍GPS 用于地质灾害滑坡地表监测的技术和方法, 并通过在四川丹巴县甲居滑坡区布设的GPS 监测网的测量, 阐述了在GPS 滑坡监测时, 监测点位选择、监测网布设、数据处理的方法.监测结果表明, GPS 滑坡监测的精度达到毫米级, 完全满足滑坡监测的精度要求.     

顾及板块运动、稳定性和系统偏差的高精度GPS监测基准研究与实现

利用GPS技术监测城市地面沉降,监测基准的合理选取对获得真实的形变结果至关重要.本文详细分析了城市沉降监测网基准的特点,针对传统基准模型的局限性提出了顾及板块运动、基准点稳定性以及其他系统误差影响的拟稳基准模型.该模型考虑了基准点自身的稳定性以及板块运动对高程形变的影响,同时采用系统参数统一各期基线框架以及区域拟稳基准,有效解决了因基准点不稳定性和基线框架不一致对形变结果造成的误差,确保正确形变信息的获取.最后通过六期西安市地面沉降监测网数据试验,验证了该方案的合理性和可靠性.     

北京市地震局GPS形变监测工作系统的建设

GPS技术在监测地震与地壳运动中已经得到应用，北京市地震局在北京市2002年启动建设的全球卫星定位综合应用服务系统基础上，于2003年开始GPS形变监测工作系统的建设，这是一个小区域连续的高密度GPS形变监测工作系统，获取高精度的北京市GPS基准站地心三维坐标，为地震监测和地壳运动的科学研究提供良好的GPS数据素材。     

抗差自适应Kalman滤波在动态变形监测中的应用研究

抗差自适应Kalman滤波算法中,抗差等价权矩阵和自适应因子的计算,要求观测信息具有多余观测量且准确可靠,但在动态变形监测应用中,通常滤波观测值仅为三维坐标且存在较强噪声和粗差的影响。为此,先对该算法中的自适应因子和抗差等价权矩阵的计算进行研究和改进,然后计算了某高速公路边坡的GPS动态监测数据。结果表明,抗差自适应Kalman滤波能够有效地抵制动态变形监测中观测值异常的影响。     

An Integrated Multi-Level Early Warning Method for Rainfall-Induced Shallow Landslides

Rainfall-induced landslides have occurred frequently in Southwestern China since the Wenchuan earthquake,resulting in massive loss of people''s life and property. Fortunately,landslide early-warning is one of the most important tools for landslide hazard prevention and mitigation. However, the accumulation of historical data of the landslides induced by rainfall is limited in many remote mountain areas and the stability of the slope is easily affected by human engineering activities and environmental changes, leading to difficulties to accurately realize early warning of landslide hazards by statistical methods. The proposed warning method is divided into rainfall warning component and deformation warning component because the deformation induced by rainfall has the characteristic of hysteretic nature. Rainfall, tilted angle and crack width are chosen as monitoring indexes. Rainfall grade level that contains rainfall intensity and duration information is graded according to the variation of the safety factor calculated by 3-D finite difference numerical simulation method, and then is applied using the strength reduction method and unascertained information theory to obtain the deformation grade level of several monitored points. Finally, based on the system reliability theory, we establish a comprehensive landslide warning level method that provides four early warning levels to reflect the safety factor reductions during and post rainfall events. The application of this method at a landslide site yield generally satisfactory results and provide a new method for performing multi-index and multi-level landslide early warnings.     

基于多卫星平台永久散射体雷达干涉提取三维地表形变速度场

永久散射体雷达干涉(PSI)技术及其应用于区域地表形变监测已成为雷达遥感领域的研究热点之一.使用单一卫星平台所获取的单侧视SAR影像时间序列进行PSI分析,仅能获取沿雷达视线(LOS)方向的一维地表位移信息.本文提出了基于多平台永久散射体雷达干涉提取三维地表形变速度场的模型与算法,其基本策略是:首先针对每一卫星平台的SAR影像时间序列进行PSI分析,并计算各地面目标沿LOS向的位移速度值,然后联合各平台所对应的LOS向位移速度值进行建模,并基于最小二乘方法解算各地面目标的三维位移速度分量.实验选取天津市西北部作为测试区,使用2007—2010年所获取的39幅TerraSAR-X影像、23幅ENVISAT ASAR影像和16幅ALOS PALSAR影像进行分析,经联合解算得到了该测试区域的垂直位移速度场以及南北向和东西向水平位移速度分量.与地面水准和已有GPS观测结果对比分析表明:多平台PSI的垂直位移速度场精度可达毫米级,而其水平位移速度分量与已有GPS结果基本一致.多平台PSI分析无需引入任何外部形变参考信息,便可以实现形变场的偏差校准和三维形变场的恢复.     

A test method for analyzing the deformation of landslide model

In order to study the overall deformation of geotechnical model conveniently, the worksite of landslide bridge foundation reinforced by the front and rear row anti-slide piles in Chenglan railway was taken as an example. On the basis of shaking tabe test of a 1/40 reduced scale model, the landslide deformation caused by vibration waves was monitored through burying self-made phosphor bronze strips in soil. Combined with the horizontal and vertical coordinates of the bending strain points on the phosphor bronze strips, the digital matrix was converted by applying Renka Cline random matrix generation method, and the two-dimensional contour plots were drawn based on it. The results showed that the two-dimensional contour plots reflected the basic law of landslide deformation reasonably, and it revealed the evolution process of landslide deformation and failure. The research conclusions were consistent with the test phenomenon, which met the basic requirements of overall deformation analysis of landslide model. This proposed method can monitor multiple cross sections and was practical for model test.     

GPS在山区滑坡变形监测中的应用

山区滑坡的稳定性一直是倍受关注的一个重要安全问题。本文讨论了滑坡位移传统监测方法的缺陷和新型的基于GPS的自动监测技术所具有的独特优势,介绍了适用于山区公路滑坡位移监测的高精度的GPS技术。实践表明,采用GPS技术进行山区滑坡的稳定性监测,具有可操作性更强、精度更高、不受气候条件约束以及高度自动化等优点,能够为预测边坡可能出现失稳破坏的部位和变形破坏时间提供更可靠的监测资料,因而GPS监测技术值得在山区滑坡的变形监测领域中推广使用。     

基于方差分量估计的多源InSAR数据自适应融合形变测量

近年来,合成孔径雷达干涉测量(Interferometric Synthetic Aperture Radar,InSAR)技术在地面沉降监测方面展现了巨大的应用潜力,但受其重访周期和一维形变测量能力的限制,仅利用单一轨道卫星观测数据很难揭示真实的地表形变特征及其演化规律.随着在轨运行的SAR卫星系统不断增加,使得融合相同时间段内覆盖同一区域的多源多轨道InSAR数据成为可能.然而目前普遍采用的多源InSAR数据融合方法均为针对大尺度形变监测设计,或者忽略南北向形变甚至水平形变,容易造成误判.为此,本文对经典小基线集(Small Baseline Subset, SBAS)时序InSAR分析方法进行改进,在其形变反演模型中加入东西向和南北向形变参数,采用方差分量估计方法解算多源观测数据验后方差,通过迭代精化确定权重矩阵,从而获得形变参数的最优估值.使用美国南加州地区的ALOS PALSAR和ENVISAT ASAR数据开展实验,利用南加州综合GPS网(SCIGN)位于研究区域内的9个站点观测数据进行验证,结果表明本文方法得到的融合形变测量结果在垂直向上能够准确反映地表形变波动,周期性与GPS观测比较一致;同时,融合得到的三维形变场显示南加州洛杉矶地区存在不可忽略的水平形变,东西向形变测量精度略高于南北向.因此,基于方差分量估计的多源InSAR融合方法在提高形变测量时间序列连续性的同时,能够更准确地反演研究区域三维形变特征.     

黄河流域刘家峡—兰州段滑坡灾害的InSAR识别及成因分析

我国滑坡灾害频发,尤其是西部地区,滑坡的隐蔽性强且危害巨大,对其灾害隐患进行早期识别对防灾减灾意义重大。传统的人工排查、大地测量等手段在山区难以开展且耗时耗力,合成孔径雷达干涉测量技术(InSAR)作为新兴的遥感测量手段,可以更精确、高效地进行大范围的滑坡灾害隐患识别。以黄河流域刘家峡-兰州段为研究区,采用永久散射体InSAR技术对覆盖该区域的111景Sentinel-1 C-SAR数据进行处理,并使用GPS数据进行趋势改正,获取研究区2014年10月—2019年12月间视距向形变场及形变特征,成功识别出1处位于永靖县的滑坡隐患区。该区的规模和量级均大于永靖县黑方台滑坡区,且未被前人提及,具有较大危险性。将InSAR结果与投影到视距向的GPS结果及前人结果进行比较,验证PS-InSAR方法的有效性;并结合历史强震资料、实地考察及时间序列对研究结果进行验证分析,结果表明该滑坡隐患区可能与1125年兰州M7.0地震和2017年九寨沟M_S7.0地震有关。本研究可为当地防灾减灾提供数据和技术支持。     

白鹤坪边坡稳定性分析

边坡监测可为掌握边坡变形特征和规律提供依据,指导在边坡发生严重变形时的应急处理。白鹤坪边坡是三峡库区的典型边坡,依据边坡的变形特征定性地认为该边坡为潜在的推移式滑坡。1998年调查发现白鹤边坡存在一定的滑移,为了对其实施监测预报、预警,减轻因其滑动而引起的地质灾害,在该边坡上建立了由10个GPS观测点组成的边坡位移观测系统,以监测边坡的变形。本文以2014年5月至2016年4月近两年的白鹤坪边坡变形观测系统所获得的位移数据为基础,对边坡的位移变形进行了统计,并结合数值模拟分析了边坡的水平向相对位移。分析表明,在边坡由缓变陡处变形显著增加,边坡现处于基本稳定状态,其变形主要受降雨影响,每年汛期时（5-10月）边坡变形量偏高。其次为库水作用影响,江水对坡脚冲蚀,使边坡前缘局部产生了小规模崩滑现象。     

北斗导航定位系统（BDS）下地壳运动监测精度分析

为分析北斗导航定位系统（BDS）在地壳运动监测领域的数据精度,选取中国大陆构造环境监测网络（陆态网络）2018—2019年川滇地区GPS、BDS多系统观测站点数据,分别对GPS、BDS记录的数据进行解算,从三维坐标解、位置时间序列及速度场等方面,对比分析二者在地壳运动监测中的不同,综合分析BDS对地壳运动监测精度。结果表明,BDS定位精度达到cm级,但仍低于GPS精度,BDS、GPS速度场模型运动方位和速度值有所不同,垂向差异较为明显。总体来看,北斗系统数据满足高精度定位解算要求,可用于监测形变量较大的区域地壳运动。     

Kinematics of landslide estimated by repeated GPS measurements in the Avcilar region of Istanbul, Turkey

The aim of this study is to analyze the spatial and temporal behavior of the landslide located in Avcilar region which is situated between Kucukcekmece and Buyukcekmece Lakes in the north-west of Marmara region, Turkey. A network consisting of 10 sites has been surveyed four times from November 2007 to May 2009 using Global Positioning System (GPS). The deformation analysis has been applied to determine the landslide movement parameters of the sites using GPS measurements of the four epochs. The reliable and high precision deformation rates are presented in terms of displacement vectors, velocity vectors and changes of accumulated strain. Landslides of the region are characterized from a regional GPS network. Each site has statistically different temporal behavior and significant relative motions and the region has irregular landslide movements.     

Extreme learning machine for the displacement prediction of landslide under rainfall and reservoir level

Landslide prediction is always the emphasis of landslide research. Using global positioning system GPS technologies to monitor the superficial displacements of landslide is a very useful and direct method in landslide evolution analysis. In this paper, an EEMD–ELM model [ensemble empirical mode decomposition (EEMD) based extreme learning machine (ELM) ensemble learning paradigm] is proposed to analysis the monitoring data for landslide displacement prediction. The rainfall data and reservoir level fluctuation data are also integrated into the study. The rainfall series, reservoir level fluctuation series and landslide accumulative displacement series are all decomposed into the residual series and a limited number of intrinsic mode functions with different frequencies from high to low using EEMD technique. A novel neural network technique, ELM, is employed to study the interactions of these sub-series at different frequency affecting landslide occurrence. Each sub-series extracted from accumulative displacement of landslide is forecasted respectively by establishing appropriate ELM model. The final prediction result is obtained by summing up the calculated predictive displacement value of each sub. The EEMD–ELM model shows the best accuracy comparing with basic artificial neural network models through forecasting the displacement of Baishuihe landslide in the Three Gorges reservoir area of China.     

某区水库大坝近期形变特征研究

通过利用GPS和水准测量手段对某区水库大坝表面运动进行监测,获取大量的野外监测数据。通过内业计算得出每期的大坝各变形点的三维坐标,并结合、利用近3期的数据资料对比,求出各点的形变量。最终通过计算、分析得出水库主坝、东副坝及北副坝3个坝体的稳定性。     

Realization of the Hungarian geodynamic GPS reference network

The Pannonian Basin, which includes Hungary, tectonically belongs to the Eurasian Plate and is considered to be relatively quiet. Detailed geological studies revealed four main tectonic units in this area—the Tisza, Pelso, Austro-Alpine and Vepor units. All of these can be genetically related to tectonic processes in the Mediterranean and Alpine-Adria region.In 1989 the Satellite Geodetic Observatory (SGO) in cooperation with several institutions has initiated the establishment of a geodynamic global positioning system (GPS) Reference Network (HGRN) for three-dimensional deformation studies in Hungary. The HGRN consists of 13 primary sites which were selected according to geological and geophysical considerations and satisfied international standards for tectonic studies with the GPS technique. Particular care was devoted to the point marks concerning mechanical stability and the repeatability of antenna set-ups at the HGRN sites, therefore a point mark and a mechanical adapter to mount the GPS antenna had been developed at the SGO for this purpose. This point mark has been used at all HGRN sites. A GPS Datum Point was also established for Hungary in 1990 at the Satellite Geodetic Observatory; here quasi continuous observations are foreseen. The Penc station has been accepted as a fiducial station of the International GPS Geodynamic Service (IGS).The zero epoch measurements were completed in fall 1991 and monitoring is planned every second year at least for the next 10 years.Preliminary processing of the data has been carried out in the SGO, Penc and at the Lustbühel Observatory at Graz, using the TRIMVEC PLUS and BERNESE V3.2 programs respectively     

Establishment of the GPS Crustal Deformation Monitoring Network in North China

The Global Positioning System (GPS) is a new method to monitor the crustal deformation for earthquake prediction.Now a four-dimensional crustal deformation monitoring network applying GPS techniques has been established in North China,which is an important seismic monitoring area.Results with high precision have been achieved in the first measurement since a series of advanced methods and measures were adopted,and thus a good foundation has been laid for future researches on earthquake prediction and geodynamics.     

地表负载及GPS测站分布对参考框架转换的影响分析

GPS数据处理通常采用Helmert七参数转换将瞬时站坐标转换到指定的框架下,但瞬时站坐标中尚未模型化的季节性地表负载会影响平移参数(地心运动)和尺度参数的估值,进而影响测站坐标;不均匀的测站分布会加剧这一影响.本文利用GRACE重力场系数仿真GPS地表负载的实验表明,基于网平移法采用实际的IGS站至少能够恢复90%的地心运动信号.地表负载及GPS实际测站的不均匀分布可以解释大约30%的GPS尺度的周年变化.相对于IGb08的所有框架站,目前采用91个全球均匀分布的核心站作为框架转换的基准是合理的.采用IGb08的所有框架站进行转换会导致U方向误差增加,特别是对框架站密集的欧洲区域(误差均值约为1mm).因此框架转换时,应尽量选取均匀分布的测站,同时不估计尺度参数.