共查询到19条相似文献，搜索用时 133 毫秒
1.
提出一种以SLR作为统一全球地壳垂直运动参考基准的方法。利用SLR、GNSS和VLBI国际分析中心提交给ITRF2008和ITRF2005的坐标速度场数据,选出精度较高的并置站,并经坐标转换计算出各自站心坐标系下的垂向速度场。基于系统差模型解算出SLR与GNSS、VLBI的垂向速度场之间的系统差,并利用此系统差将GNSS、VLBI的垂向速度场改正到以SLR为垂直运动参考基准上来。经一致性检验发现,改正后相关系数和斜率都趋近于1,这表明以SLR作为统一地壳垂直运动参考基准是可行的。 相似文献
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当前地震、地质灾害等现象的频繁发生,表明对于地壳运动尤其是垂直方向的研究是迫切而必需的,而研究垂直地壳运动的一个重要前提就是其参考基准的确立。针对目前国内外对于全球垂直地壳运动参考基准不统一的现状,分析了研究全球统一的垂直地壳运动参考基准的必要性,提出将ITRF2008框架下获取的SLR的垂向速度场作为全球垂直地壳运动参考基准的方案,论证了该方案的合理性,并利用GPS和VLBI的观测数据,求取了其速度场与SLR垂直基准之间的系统差,分析了产生不同大小且方向各异系统差的原因,实现了各速度场与全球垂直地壳运动参考基准的统一。由于该基准包含了较为丰富的地球物理信息,具有可发展、可提高以及直接相对于地球质心等特性,因此,我们推荐将ITRF2008框架下SLR技术获取的垂向速度场定义为全球垂直地壳运动的参考基准。 相似文献
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简要分析了最新的国际地球参考框架ITRF2005实现的基本情况及其相对于ITRF2000的改进,以ITRF2005为参考框架建立了新的全球板块运动模型ITRF2005VEL。建模时,首先根据测站的分布和速度场的精度对测站进行初步剔除,然后采用相似变换的方法对全球ITRF2005测站的速度场数据再进行第2次筛选。根据筛选结果利用最小二乘方法建立了全球板块运动背景场及其运动模型,给出了全球11个主要块体的运动参数。此结果与其他学者建立的模型相比,总体上有很好的一致性,但在个别块体上也有所差异。 相似文献
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简要分析了最新的国际地球参考框架ITRF2005实现的基本情况及其相对于ITRF2000的改进,以ITRF2005为参考框架建立了新的全球板块运动模型ITRF2005VEL.建模时,首先根据测站的分布和速度场的精度对测站进行初步剔除,然后采用相似变换的方法对全球ITRF2005测站的速度场数据再进行第2次筛选.根据筛选结果利用最小二乘方法建立了全球板块运动背景场及其运动模型,给出了全球11个主要块体的运动参数.此结果与其他学者建立的模型相比,总体上有很好的一致性,但在个别块体上也有所差异. 相似文献
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广西区域现今地壳运动与应变的GPS监测分析 总被引：1，自引：0，他引：1
利用GAMIT/GLOBK软件分析了1998-2010年间多期GPS观测数据,获得了ITRF2005框架下广西区域现今地壳运动三维速度场和应变场参数,并对区域形变场和现今构造运动动力学机制进行了初步讨论。GPS监测结果显示:广西区域现今地壳运动随华南块体作南东东方向的逆时针构造运动,ITRF2005框架下水平方向平均速率为33.49 mm/a,优势方向为N 109.3° E;垂直方向平均速率为+1.30 mm/a,整体趋势是自桂东向桂西方向垂向速率逐步增加。现今应变状态以N 127.3°±4.8° E挤压为主,最大主压应变率-2.7±0.5×10-9/a;兼有N 37.3°±4.8° E方向的拉张作用,最大主张应变率1.8±0.2×10-9/a。本文研究结果为描述广西区域现今地壳运动提供了一个更加精细的三维速度场。 相似文献
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山西CORS网基准站速度场分析 总被引：1，自引：0，他引：1
利用GAMIT/GLOBK软件处理山西CORS基准站2009-05～2011-02期间将近2a的数据,确定了基准站的坐标时间序列和速度场,并分析了山西省地壳运动。结果表明,山西CORS基准站在ITRF2005框架下水平方向运动的平均速率为33.97mm·a-1,运动方向为SEE110.55;相对于欧亚板块的水平方向运动的平均速率为6mm·a-1,运动方向为SE130.69。此外,SXCORS基准站在ITRF2005框架下的垂直速度场的变化规律为绝大多数地区发生沉降,且南部地区的沉降速率大于北部地区,沉降的主要原因是由于地下水的长期开采和超采以及煤炭的开采,并且该现象在南部地区更为严重。 相似文献
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《测绘科技情报》2008,(2)
与之前的国际地球参考框架(ITRF)将全球长期解作为输入数据进行组合不同,ITRF2005将测站坐标(卫星技术每星期的数据和VLBI每24小时的数据)和每天的地球自转参数(EOPs)作为输入数据。使用测站位置时间序列的优势在于可以监控测站的非线性运动和非连续性,并检验框架物理参数即原点和尺度的时变特性。ITRF2005原点定义为:相对于由SLR技术13年的观测数据所得的地球质心的平移和平移速度为零;尺度定义为:相对于由VLBI技术26年的观测数据所得的尺度及其变化率为零;ITRF2005的定向(2000.0历元)及其速率与ITRF2000中70个高质量的测站一致。ITRF2005原点(2000.0历元)及其速率相对于ITRF2000沿X,Y,Z轴在0.1,0.8,5.8mm和0.2,0.1,1.8mm/y的水平上一致,其分量的误差分别为0.3mm和0.3mm/y。两个参考框架原点间一致性差可能是因为SLR网的几何图形差。ITRF2005组合中包含了84个并置站,尺度的不一致性在2000.0历元为1ppb(赤道处为6.3mm),SLR和VLBI由各自时间序列堆栈得到的长期解之间尺度不一致性为0.08ppb/yr。这些不一致性可能是因为SLR和VLBI网形差、并置站质量不好、局部联系的不确定性、系统误差影响以及数据分析中模型改正的不一致性。ITRF历史上,ITRF2005第一次采用了紧组合的方式给出了与之相一致的EOP序列,包括由VLBI和卫星技术得到的极移和仅从VLBI得到的UT和日长数据。 相似文献
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利用 1 988～ 1 996年共 8年的上海天文台 VLBI站与国际 VLBI站基线长度变化的精确测定结果 ,重新估计了上海 VL BI站的形变速率 ,证实了基于不同地球参考架系统对估计的上海站的运动有明显差异 ;基于最新的 ITRF96地球参考架和 Sillard等 (1 998)欧亚板块的欧拉矢量 ,估计得到上海站的地壳垂直形变速率为 -1 .95± 1 .0 2 mm/a呈下降趋势 ,水平形变速率为 1 3.5 5± 1 .2 0 mm/a,方位 77.5°± 4.5°;估计得到乌鲁木齐 VL BI站的地壳垂直形变速率为 -6 .0 8± 2 .77mm/a呈下降趋势 ,水平形变速率为 2 1 .87± 2 .5 2 mm/a,方位 45 .5°±6 .6°;进一步分别基于 NNR-NUVEL -1 A地球板块运动模型和 Zhang等 (1 999)的欧亚板块的欧拉矢量 ,得到与上述较一致的结果 相似文献
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ITRF2000参考架的评价及其探讨 总被引：2，自引：1，他引：2
通过ITRF2 0 0 0速度场建立完全独立于任何地质模型假设的ITRF2 0 0 0VEL模型 ,求出总角动量 |L|为 0 .12 7°/m·a ,在运动中应加以改正 ,从而实现无整体旋转参考架 相似文献
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利用欧拉定律和ITRF2005的速度场,给出了全球板块运动模型ITRF2005VEL,并计算了全球地壳旋转总角动量之和。采用离散的Tisserand条件对实测的全球台站运动速度进行约束,建立了一个新的基于NNR参考框架的实测的绝对板块运动模型NNR-ITRF2005,并与地学模型NNR-NUVEL1A和ITRF其他序列建立的NNR模型进行了比较和分析。结果表明,从整体上来看,NNR-ITRF2005比较接近于NNR-NU-VEL1A,但个别板块由于测站较少、分布不均或者测站观测时间短对板块的约束不够等原因,使得这些板块的欧拉极与地学模型的偏差较大。 相似文献
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对近年来精度高、应用较多的国际地球参考架ITRF2005做了简单概述,指出了ITRF2000与ITRF2005之间在解的生成、基准的定义和实现等方面的不同。此外,ITRF2005除了包含作为参考框架体现的站点坐标和速率之外,还包含一起参与联合处理的地球定向参数：极移、极移速率、日长、UT1的时间序列[1]。重点阐明ITRF2005的实现的基本情况及其相对于ITRF2000所作改进的理由和合理性。 相似文献
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The proper identification and removal of outliers in the combination of rates of vertical displacements derived from GPS,
tide gauges/satellite altimetry, and GRACE observations is presented. Outlier detection is a necessary pre-screening procedure
in order to ensure reliable estimates of stochastic properties of the observations in the combined least-squares adjustment
(via rescaling of covariance matrices) and to ensure that the final vertical motion model is not corrupted and/or distorted
by erroneous data. Results from this study indicate that typical data snooping methods are inadequate in dealing with these
heterogeneous data sets and their stochastic properties. Using simulated vertical displacement rates, it is demonstrated that
a large variety of outliers (random scattered and adjacent, as well as jointly influential) can be dealt with if an iterative
re-weighting least-squares adjustment is combined with a robust median estimator. Moreover, robust estimators are efficient
in areas weakly constrained by the data, where even high quality observations may appear to be erroneous if their estimates
are largely influenced by outliers. Four combined models for the vertical motion in the region of the Great Lakes are presented.
The computed vertical displacements vary between − 2 mm/year (subsidence) along the southern shores and 3 mm/year (uplift)
along the northern shores. The derived models provide reliable empirical constraints and error bounds for postglacial rebound
models in the region. 相似文献
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利用长江三角洲区域内19个GPS连续运行参考站2007～2013年间的观测数据,计算得到了该区域ITRF2005参考框架下的三维速度场、应变参数及区域参考框架下的速度场。结果表明,在ITRF2005框架下,水平方向平均速率为33.97 mm/a,优势方向为NE 111.5°;相对于欧亚板块的水平方向平均速率为9.36 mm/a,优势方向为NE 85.6°;高程方向以沉降为主,最大沉降速率为15.22 mm/a,平均沉降速率为4.7 mm/a;该区域块体以N 29.4° E的拉张为主,达到2.4×10-9/a,同时兼有N 119.4° E的挤压,达到1.3×10-9/a。 相似文献
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VLBI terrestrial reference frame contributions to ITRF2008 总被引：6，自引：5，他引：1
In late 2008, the Product Center for the International Terrestrial Reference Frame (ITRF) of the International Earth Rotation
and Reference Systems Service (IERS) issued a call for contributions to the next realization of the International Terrestrial
Reference System, ITRF2008. The official contribution of the International VLBI Service for Geodesy and Astrometry (IVS) to
ITRF2008 consists of session-wise datum-free normal equations of altogether 4,539 daily Very Long Baseline Interferometry
(VLBI) sessions from 1979.7 to 2009.0 including data of 115 different VLBI sites. It is the result of a combination of individual
series of session-wise datum-free normal equations provided by seven analysis centers (ACs) of the IVS. All series are completely
reprocessed following homogeneous analysis options according to the IERS Conventions 2003 and IVS Analysis Conventions. Altogether,
nine IVS ACs analyzed the full history of VLBI observations with four different software packages. Unfortunately, the contributions
of two ACs, Institute of Applied Astronomy (IAA) and Geoscience Australia (AUS), had to be excluded from the combination process.
This was mostly done because the IAA series exhibits a clear scale offset while the solution computed from normal equations
contained in the AUS SINEX files yielded unreliable results. Based on the experience gathered since the combination efforts
for ITRF2005, some discrepancies between the individual series were discovered and overcome. Thus, the consistency of the
individual VLBI solutions has improved considerably. The agreement in terms of WRMS of the Terrestrial Reference Frame (TRF)
horizontal components is 1 mm, of the height component 2 mm. Comparisons between ITRF2005 and the combined TRF solution for
ITRF2008 yielded systematic height differences of up to 5 mm with a zonal signature. These differences can be related to a
pole tide correction referenced to a zero mean pole used by four of five IVS ACs in the ITRF2005 contribution instead of a
linear mean pole path as recommended in the IERS Conventions. Furthermore, these systematics are the reason for an offset
in the scale of 0.4 ppb between the IVS’ contribution to ITRF2008 and ITRF2005. The Earth orientation parameters of seven
series used as input for the IVS combined series are consistent to a huge amount with about 50 μas WRMS in polar motion and
3 μs in dUT1. 相似文献
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Evaluation of the ITRF2008 GPS vertical velocities using satellite antenna z-offsets 总被引：2，自引：0，他引：2
We develop a method to evaluate the terrestrial reference frame (TRF) scale rate error using Global Positioning System (GPS) satellite antenna phase center offset (APCO) parameters and apply it to ITRF2008. We search for the TRF in which z-APCO parameters have the smallest drift. In order to provide realistic error bars for the z-APCO drifts, we pay attention to model periodic variations and auto-correlated noise processes in the z-APCO time series. We will show that the GPS scale rate with respect to a frame is, as a first approximation, proportional to the estimated mean z-APCO trend if that frame is used to constrain station positions. Thus, an ITRF2008 scale rate error between ?0.27 and ?0.06 mm/yr depending on the GPS analysis center can be estimated, which demonstrates the high quality of the newly constructed ITRF2008. We will also demonstrate that the traditional estimates of the GPS scale rate from 7-parameter similarity transformations are consistent with our newly derived GPS scale rates with respect to ITRF2008 within two sigmas. We find using International GNSS Service (IGS) products that the traditional approach is relevant for scale rate determination even if some of the z-APCO values supplied by the IGS were not simultaneously calibrated. As the scale rate is related to the accuracy of vertical velocities, our estimates supply a conservative evaluation that can be used for error budget computation. 相似文献
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ITRF2000和新的全球板块运动模型 总被引：6，自引：0，他引：6
地学工作者一直关注的ITRF2000地球参考框架初步结果已于2001年3月19日公布，ITRF2000综合了VLBI、SLR，LLR，GPS和DORIS技术，产生736个点位坐标和54个核心站，文中介绍了ITRF2000，并利用ITRF2000综合解的结果计算全球板块的欧拉矢量，建立了基于空间实测数据基础 的最新全球板块运动模型。 相似文献
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IGS contribution to the ITRF 总被引：2，自引：0，他引：2
We examine the contribution of the International GNSS Service (IGS) to the International Terrestrial Reference Frame (ITRF) by evaluating the quality of the incorporated solutions as well as their major role in the ITRF formation. Starting with the ITRF2005, the ITRF is constructed with input data in the form of time series of station positions (weekly for satellite techniques and daily for VLBI) and daily Earth Orientation Parameters. Analysis of time series of station positions is a fundamental first step in the ITRF elaboration, allowing to assess not only the stations behavior, but also the frame parameters and in particular the physical ones, namely the origin and the scale. As it will be seen, given the poor number and distribution of SLR and VLBI co-location sites, the IGS GPS network plays a major role by connecting these two techniques together, given their relevance for the definition of the origin and the scale of the ITRF. Time series analysis of the IGS weekly combined and other individual Analysis Center solutions indicates an internal precision (or repeatability) <2 mm in the horizontal component and <5 mm in the vertical component. Analysis of three AC weekly solutions shows generally poor agreement in origin and scale, with some indication of better agreement when the IGS started to use the absolute model of antenna phase center variations after the GPS week 1400 (November 2006). 相似文献