共查询到19条相似文献，搜索用时 171 毫秒
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针对单一平台DInSAR技术仅能获取雷达视线方向同震形变场的问题,根据雷达成像的几何条件,融合不同轨道、不同平台的DInSAR数据解算了拉奎拉地震的三维同震形变场。三维形变结果反映的拉奎拉地震发震断层的特征与地质调查的结果较吻合。将得到的三维形变场数据与该地区GPS观测站数据进行比较,结果表明,得到的拉奎拉地震的三维同震形变场比较可靠且精度较高。 相似文献
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为进一步分析并评定基于三角网提取的鄂尔多斯块体东北缘垂直形变速率等值线的精度,本文结合基于格网提取的同区域垂直形变速率等值线,分别从数字高程模型(Digital Elevation Model,简称DEM)建立与等值线提取两个角度对研究成果的精度进行对比分析,进而综合两个角度对两种方法提取的垂直形变速率等值线精度进行了差值比较。结果表明,在等值线基值与等值距都相同的条件下,研究区域垂直形变三角网的平均坡度较大,利用三角网提取的垂直形变速率等值线其精度相对较高。 相似文献
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基于中国大陆构造环境监测网络的连续GPS观测数据,比较分析了中国大陆234个GPS台站和GRACE得到的地表垂直形变。GPS和GRACE垂直形变具有较好的一致性,反映了地表质量变化是引起GPS垂直形变非线性变化的重要因素之一,但二者也存在着一定的差异。为定量分析GPS和GRACE垂直形变的差异,探讨了热膨胀效应对GPS垂直位移的影响及区域地壳结构对GRACE估算地表垂直负荷形变的影响。结果表明,中国大陆50%以上的GPS台站热膨胀垂直形变周年振幅不小于1 mm;对GPS进行热膨胀效应改正后,中国大陆GPS与GRACE垂直形变具有更好的一致性;GPS与GRACE垂直形变周年振幅比值由1.07±0.06变为1.01±0.05;热膨胀效应可以解释6.2%的GPS与GRACE垂直形变的差异,热膨胀效应改正可使GPS和GRACE垂直形变的一致性相对增加11.2%。是否顾及区域地壳结构引起的GRACE估算中国大陆垂直负荷形变的相对差异为2.5%。 相似文献
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分析了克里金插值算法中,GPS台站分布在地表垂向形变监测中的影响。通过将GPS台站观测得到的垂直形变数据进行克里金插值,得到区域地表垂向形变场。实验表明,均匀布设GPS台站时,克里金插值算法得到的区域地表形变场整体效果较好;在形变量较大或形变梯度较高位置,更密的GPS台站分布有助于得到精度更高的形变场。 相似文献
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根据InSAR观测量对南北向形变不敏感的特点,将内插GPS数据得到的南北向形变场信息和InSAR监测数据进行集成和融合解算,提取三维形变场。该方法有效避免了因直接忽略南北向形变而带来的精度影响问题,较好地改善了垂向形变场的反演精度。以西安市作为研究区域,融合EnviSat ASAR、ALOS PALSAR及GPS数据,反演西安市2009—2010年在东西向和垂向的绝对的年平均形变速率场(形变场),并与11个水准监测结果进行比对,发现融合反演法不仅能提供三维形变场,而且反演的垂向精度明显优于忽略南北向形变后的反演形变结果,从而对西安市地表形变有更深入的认识。 相似文献
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全面分析重力测量的各种误差和目前能达到的精度后，对垂直形变监测中引入重力观测值的可行性进行了具体研究。结果表明，若仅是为了测定点的垂直位移的高程速率，增加重力测量数据后对形变分析的精度增益十分有限。但是对于大跨度垂直形变监测和局部地区突发性垂直形变测定，重力测量方法可以及时掌握垂直形变的趋势 相似文献
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Analytical optimization of a DInSAR and GPS dataset for derivation of three-dimensional surface motion 总被引：2，自引：0，他引：2
A revised method for derivation of three-dimensional surface motions maps from sparse global positioning system (GPS) measurements and two differential interferometric synthetic aperture radar (DInSAR) interferograms based on a random field theory and Gibbs-Markov random fields equivalency within Bayesian statistical framework is proposed. It is shown that the Gibbs energy function can be optimized analytically in the absence of a neighboring relationship between sites of a regular lattice. Because the problem is well posed, its solution is unique and stable, and additional regularization in the form of smoothness is not required. The proposed algorithm is simple in realization, does not require extensive computer power, and is very quick in execution. The results of inverse computer modeling are presented and show a drastic improvement of accuracy when both GPS and DInSAR data are used. 相似文献
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针对传统的欧拉(Euler)矢量法在具有复杂构造运动的区域地区内构建GPS速度场模型精度低的问题,该文提出了欧拉矢量法结合遗传算法(GA)和BP神经网络方法来构建区域GPS速度场。以云南区域1999—2015年间的GPS速度场为实验数据,分别使用欧拉矢量法、遗传神经网络(GABP)、欧拉矢量结合神经网络(Euler-BP)和欧拉矢量的遗传神经网络(Euler-GABP)法构建区域速度场模型。实验结果表明,相比其他3种方法,该文提出的Euler-GABP方法在构建区域GPS速度场模型是可行和有效的且精度高。 相似文献
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近年来,有研究发现在GPS测站坐标时间序列中既存在白噪声,也存在有色噪声。为了研究有色噪声对东南极区域GPS测站三维速度估计的影响,本文使用GAMIT/GLOBK10.5软件对东南极区域6个连续GPS测站2005—2014年的实测数据进行解算和平差,并利用最大似然法（MLE）分别估计了在两种假设噪声模型条件下的测站三维运动速度及其不确定性。结果表明：在进行参数估计时,考虑两种有色噪声（闪烁噪声和随机游走噪声）对东南极区域GPS测站三维速度估计的量级影响不大,水平方向最大影响量级为0.3 mm/a,垂直方向最大影响量级为0.8 mm/a;但如果不考虑有色噪声,会严重低估参数估计的真实不确定性。 相似文献
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合成孔径雷达差分干涉测量(Differential Interferometric Synthetic Aperture Radar,DInSAR)在低相关区由于受时间空间去相关的影响,无法得到有效应用。角反射器DInSAR方法能在长时间段内保持幅度和相位稳定性,可以最大程度地减小去相关的影响。但由于反射器在空间上一般形成不规则稀疏网络分布,在平地相位、高程相位计算及相位展开方法上都带来新的挑战。研究三角反射器的DInSAR技术,重点分析基于不规则离散点的最小费用流相位展开算法。对费用流算法权重的选择,通过分析残差的产生来源,提出以弧所穿越的边长度倒数作为弧费用的权重设置方法,解决费用流算法中具有相同费用路径的选择问题。最后将角反射器DInSAR技术应用于滑坡移动的监测,通过对140d时间段的监测,得到与实测值具有较好一致性的结果。 相似文献
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利用多面函数双调和法,采用中国地壳运动观测网络一期正式公布的GPS速度场（模型A）和从该速度场中剔除不可靠速度场值的数据（模型B）分别构建了中国大陆三维速度场模型。由于多面函数双调和法只是对速度场拟合,参与建模的异常值对模型构建几乎没有影响,但由于GPS得到的垂直速度场较水平速度场精度要低,同时易受到非构造形变和区域不均匀沉降的影响,剔除不可靠值后的三维模型（即模型B）表现出更好的自洽性,其水平方向与以往所建立的模型一致,垂直方向与通过Delaunay三角网内插建立的模型符合较好。进一步分析显示,我国大部分地区垂直方向的速度场接近于零,但天津、保定、上海附近有明显的下沉趋势,最大下沉速率可达50±4．6mm／a。 相似文献
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Since the Selective Availability was turned off, the velocity and acceleration can be determined accurately with a single GPS receiver using raw Doppler measurements. The carrier-phase-derived Doppler measurements are normally used to determine velocity and acceleration when there is no direct output of the raw Doppler observations in GPS receivers. Due to GPS receiver clock drifts, however, a GPS receiver clock jump occurs when the GPS receiver clock resets itself (typically with 1 ms increment/decrement) to synchronize with the GPS time. The clock jump affects the corresponding relationship between measurements and their time tags, which results in non-equidistant measurement sampling in time or incorrect time tags. This in turn affects velocity and acceleration determined for a GPS receiver by the conventional method which needs equidistant carrier phases to construct the derived Doppler measurements. To overcome this problem, an improved method that takes into account, GPS receiver clock jumps are devised to generate non-equidistant-derived Doppler observations based on non-equidistant carrier phases. Test results for static and kinematic receivers, which are obtained by using the conventional method without reconstructing the equidistant continuous carrier phases, show that receiver velocity and acceleration suffered significantly from clock jumps. An airborne kinematic experiment shows that the greatest impact on velocity and acceleration reaches up to 0.2 m/s, 0.1 m/s2 for the horizontal component and 0.5 m/s, 0.25 m/s2 for the vertical component. Therefore, it can be demonstrated that velocity and acceleration measurements by using a standalone GPS receiver can be immune to the influence of GPS receiver clock jumps with the proposed method. 相似文献
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Qiang Chen Guoxiang Liu Xiaoli Ding Jyr-Ching Hu Linguo Yuan Ping Zhong M. Omura 《International Journal of Applied Earth Observation and Geoinformation》2010
A method for tightly integrating GPS observations and the persistent scatterer (PS) interferometric synthetic aperture radar (InSAR) is proposed to detect vertical ground motion in Hong Kong, China. The tropospheric zenith wet delays (ZWD) derived from GPS observations at sites in the SAR scenes are used first to model and correct for the tropospheric effects in the interferograms generated from the SAR images. The vertical motion rates (VMR) of the GPS sites determined based on the continuous GPS observations obtained at the sites are then used as constraints in the PS InSAR solutions to further enhance the quality of the solutions. Data from 12 continuous tracking GPS sites in Hong Kong and 8 ENVISAT ASAR images acquired during 2006–2007 are used to demonstrate the application of the proposed method. The results from the example show that the method is capable of detecting accurately the vertical ground motion. 相似文献
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Yunfeng Tian 《地球空间信息科学学报》2013,16(3):207-215
The nearly nine-year continuous GPS data collected since 1 March 1999 from the Crustal Motion Observation Network of China (CMONOC) were consistently analyzed. Most of the nonlinear movements in the cumulative position time series produced by CMONOC data center disappeared; and more accurate vertical terms and tectonic signals were extracted. Displacements caused by atmospheric pressure loading, nontidal ocean loading, soil moisture mass loading, and snow cover mass loading using the National Centers for Environmental Prediction (NCEP) Reanalysis I/II models and Estimation of the Circulation and Climate of the Ocean (ECCO) data can explain most of the vertical annual terms at many stations, while only parts can be explained at Lhasa and southern coastal sites, indicating that there are some deformation mechanisms that are still unknown or not modeled accurately. The remarkable differences in vertical position time series for short-baseline sites reveal that GPS stations can be greatly affected by local factors; and attention should be paid when explaining observed GPS velocity vectors. 相似文献
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The nearly nine-year continuous GPS data collected since 1 March 1999 from the Crustal Motion Observation Network of China(CMONOC) were consistently analyzed.Most of the nonlinear movements in the cumulative position time series pro-duced by CMONOC data center disappeared;and more accurate vertical terms and tectonic signals were extracted.Displacements caused by atmospheric pressure loading,nontidal ocean loading,soil moisture mass loading,and snow cover mass loading using the National Centers for Environmental Prediction(NCEP) Reanalysis I/II models and Estimation of the Circulation and Climate of the Ocean(ECCO) data can explain most of the vertical annual terms at many stations,while only parts can be explained at Lhasa and southern coastal sites,indicating that there are some deformation mechanisms that are still unknown or not modeled accurately.The remarkable differences in vertical position time series for short-baseline sites reveal that GPS stations can be greatly affected by lo-cal factors;and attention should be paid when explaining observed GPS velocity vectors. 相似文献