共查询到18条相似文献，搜索用时 125 毫秒
1.
由于利用GAMIT/GLOBK软件对连续运行多年的GPS基准站数据进行处理的原始结果存在一定的噪声,本文利用ARMA模型对GPS基准站坐标进行时间序列分析,其中采用Pandit-Wu方法确定ARMA模型的阶数.试验结果表明,采用Pandit-Wu方法能够准确地确定ARMA模型的阶数,并且基于ARMA的时间序列有效地消除了一定量的噪声,让GPS基准站随着时间的变化规律与趋势更加明显,说明ARMA模型在GPS基准站坐标时间序列分析中剔除噪声及突显变化量与趋势具有良好的效果. 相似文献
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本文描述了CORS站高程时间序列采用固定周期项建立线性速度场的基本概念，指出给定周期与实际周期存在偏差的问题。为此，提出了CORS站高程时间序列非线性速度场建模方法。该方法以线性最小二乘解作为迭代初值，利用高斯-牛顿迭代算法求解非线性速度场模型的未知参数，实现了CORS站高程时间序列数据的非线性建模；给出了拟合模型残差平方序列异方差特性的检验方法，阐述了建立GARCH（p，q）模型反映CORS站高程非平稳序列波动情况的基本准则。本文以国内外6个CORS站20余年的高程时间序列为研究对象，建立非线性速度场运动模型。结果表明：CORS站高程运动并不存在严格的整年或半年周期项，近似年周期运动最为明显，近似两年周期运动占比最小，年周期估计偏差达到12%，半年周期偏差18%，两年周期偏差6%，非线性建模精度和效果整体优于线性模型。利用ARCH检验法得到CORS站高程非线性模型的残差平方序列存在异方差性，即残差平方序列具有非平稳特性，引入GARCH（p，q）模型对CORS站高程分量非平稳残差平方序列建模，反映了残差平方序列的非平稳波动。验证了GARCH（p，q）模型对CORS站高程非平稳残差平方序列建模的可行性，为今后利用GARCH（p，q）模型对CORS站高程非平稳噪声序列建模和非线性速度场重构提供了思路。 相似文献
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回顾经验模式分解技术的原理和滤波性质,及目前基于经验模式分解的滤波去噪算法,包括部分本征函数模态分量重构法、软阈值法、最优信号重构算法等;分析上述滤波方法在分离信号噪声方面的适用性及其可能的改进措施;最后讨论传统的周期函数拟合模型在GPS高程时间序列噪声提取中应用的局限性,提出经验模式分解应用于GPS高程时间序列噪声提取与研究的新思路。 相似文献
4.
GPS高程数据时间序列分析 总被引：4，自引：1，他引：4
对GPS台站时间序列进行了研究，对我国IGS连续跟踪站高程分量的数据进行谱分析和小波分析，用最小二乘法将时间序列的白噪声与有色噪声分离，并利用AR模型建模。通过分析，获得拉萨、上海和武汉GPS连续跟踪站的有色噪声特征。 相似文献
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中国大陆GPS基准站的时间序列特征 总被引：1，自引：0，他引：1
利用1999年3月至2002年3月期间“中国地壳运动观测网络”25个GPS基准站与周边国家IGS站的观测资料，进行了时间序列分析研究，并对提高GPS基准站的观测精度进行了探讨。结果表明，GPS基准站的时间序列具有一定的周期性，高程分量的周期性最为明显，GPS点位高程时间序列拟舍曲线的波峰和波谷出现的时间表现为区域性的不同。 相似文献
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利用小波变换分解变形监测数据,重构分离得到低频线性项和高频非线性项,线性特征强的子序列使用ARMA模型进行建模预报,非线性特征强的子序列使用神经网络模型进行建模预报,最后合成获得预报值。文中使用隔河岩大坝GPS变形监测数据进行建模预报,分析小波分解层数对预报精度的影响,提出平滑测度确定分解层数的方法,比较ARMA模型或神经网络模型和小波分解下的组合模型的预报精度,结果表明组合模型的预报精度优于单一模型,其精度在0.6mm,最大偏差为1.6mm,平均改善76%和77%。 相似文献
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我国GPS跟踪站数据处理与时间序列特征分析 总被引：1，自引：0，他引：1
应用国内GPS跟踪站7a的观测数据，分析研究跟踪站坐标位置变化规律，并给出了站坐标和速度场精度的统计分析结果，同时介绍了国内GPS基准站的数据处理方法。通过对时间序列进行分析研究表明，GPS基准站的时间序列具有一定的周期性，高程分量的周期性最为明显，并且时间序列的时频特性表现出明显的区域性。 相似文献
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Annual deformation signals from homogeneously reprocessed VLBI and GPS height time series 总被引：3，自引：3，他引：0
Volker Tesmer Peter Steigenberger Markus Rothacher Johannes Boehm Barbara Meisel 《Journal of Geodesy》2009,83(10):973-988
The first part of this paper compares homogeneously reprocessed Very Long Baseline Interferometry (VLBI) and Global Positioning
System (GPS) long-term height series from 1994 to 2007. The data analysis used fully adapted state-of-the-art models (like
VMF1 and a priori zenith delays from ECMWF) for the GPS and VLBI processing. The series are compared in terms of long-term
non-linear behaviour, harmonic and mean annual signals (not necessarily of harmonic nature). The similarity between both techniques
is very good (especially the mean annual signals), which is assumed to be due to the adapted models and consistent reprocessing
of both series. As two almost independent observing techniques see the same annually recurring signals at almost all co-located
sites, we expect a good geophysical interpretability as integral vertical deformation. For the second part of this paper,
the height time series of 161 suitable GPS sites (of the same solution as before) are used to determine a harmonic and a mean
annual signal for each of them. Comparing the annual signals for this big dataset visually to GRACE-determined load deformations
described in other publications, we find good agreement. This puts emphasis to the assumption that our height data have a
lot of potential to be interpreted as geophysical signals. Out of these 161, 131 are grouped to 55 clusters, if at least two
nearby (some thousand kilometres) sites show similar mean annual signals, which are thus confirmed to be real regional deformation,
not local or technical artefacts. These 55 signals are presented on a “world map” of regional average mean annual height signals,
as easy-to-handle tool to validate geophysical models. The data of these measured regional mean annual signals can be downloaded
from a web-page for numerical analysis. 相似文献
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阐述了GPS共视法的基本原理,讨论了利用重力频移法通过GPS共视观测数据确定重力位差和高程差的方法。利用国际权度局(BIPM)发布的时间序列数据,选取了4个守时台站之间的时间差序列进行实验。结果表明,受目前GPS共视法精度所限,高程差计算值与理论值之间的平均差异和标准差在几十m的量级水平。 相似文献
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Comparative analysis of different environmental loading methods and their impacts on the GPS height time series 总被引：1，自引：1，他引：0
Three different environmental loading methods are used to estimate surface displacements and correct non-linear variations in a set of GPS weekly height time series. Loading data are provided by (1) Global Geophysical Fluid Center (GGFC), (2) Loading Model of Quasi-Observation Combination Analysis software (QLM) and (3) our own daily loading time series (we call it OMD for optimum model data). We find that OMD has the smallest scatter in height across the selected 233 globally distributed GPS reference stations, GGFC has the next smallest variability, and QLM has the largest scatter. By removing the load-induced height changes from the GPS height time series, we are able to reduce the scatter on 74, 64 and 41 % of the stations using the OMD models, the GGFC model and QLM model respectively. We demonstrate that the discrepancy between the center of earth (CE) and the center of figure (CF) reference frames can be ignored. The most important differences between the predicted models are caused by (1) differences in the hydrology data from the National Center for Atmospheric Research (NCEP) vs. those from the Global Land Data Assimilation System (GLDAS), (2) grid interpolation, and (3) whether the topographic effect is removed or not. Both QLM and GGFC are extremely convenient tools for non-specialists to use to calculate loading effects. Due to the limitation of NCEP reanalysis hydrology data compared with the GLDAS model, the GGFC dataset is much more suitable than QLM for applying environmental loading corrections to GPS height time series. However, loading results for Greenland from GGFC should be discarded since hydrology data from GLDAS in this region are not accurate. The QLM model is equivalent to OMD in Greenland and, hence, could be used as a complement to the GGFC product to model the load in this region. We find that the predicted loading from all three models cannot reduce the scatter of the height coordinate for some stations in Europe. 相似文献
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与传统测量方式比较,全球定位系统(global positioning system,GPS)测量具有定位精度高、测量时间短、操作简单、全天候作业等优势,利用GPS观测得到的大地高拟合成正常高可以大大提高测绘效率。研究了二次曲面法拟合似大地水准面模型,以豫北某区域为研究区,分别作整体区域二次曲面拟合和分区二次曲面拟合,并进行精度分析,结论如下:通过提高GPS测量的大地高精度和选用高精度的联测水准点,能够有效提高拟合后的高程精度;测区面积较大和测区地形起伏较大时,采用分区拟合高程的精度相对于整体区域拟合的精度会大大提高。 相似文献
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GPS时间序列的空间滤波可以提高观测数据的信噪比，有利于获取更高精度的地壳形变信息。区域叠加滤波算法的空间滤波结果随着测站数和空间尺度不同而不同，不利于研究GPS时间序列中的形变信息。为了削弱区域叠加滤波受空间尺度的影响，提出一种不以空间尺度作为约束条件，同时引入相关系数和距离因子的区域叠加滤波算法。采用2010—2017年中国区域260个GPS连续观测站的时间序列展开空间滤波方法的研究，计算结果表明，对比相关性区域叠加滤波算法，考虑GPS时间序列之间的相关系数和距离因子更有利于提取GPS时间序列中的共模误差，且受空间尺度的影响较小。对比3种不同距离因子的区域叠加滤波算法，可知引入距离反比的空间滤波算法可实现更优的空间滤波。采用该方法空间滤波后可使GPS时间序列残差降低30%~40%，GPS速度场精度提高30%~40%。此算法实现了更优的GPS形变场估计，为研究中国区域的地壳运动和其动力学机制提供了可靠的数据基础。 相似文献
16.
Xavier Collilieux Laurent Métivier Zuheir Altamimi Tonie van Dam Jim Ray 《GPS Solutions》2011,15(3):219-231
The International GNSS Service (IGS) contributes to the construction of the International Terrestrial Reference Frame (ITRF)
by submitting time series of station positions and Earth Rotation Parameters (ERP). For the first time, its submission to
the ITRF2008 construction is based on a combination of entirely reprocessed GPS solutions delivered by 11 Analysis Centers
(ACs). We analyze the IGS submission and four of the individual AC contributions in terms of the GNSS frame origin and scale,
station position repeatability and time series seasonal variations. We show here that the GPS Terrestrial Reference Frame
(TRF) origin is consistent with Satellite laser Ranging (SLR) at the centimeter level with a drift lower than 1 mm/year. Although
the scale drift compared to Very Long baseline Interferometry (VLBI) and SLR mean scale is smaller than 0.4 mm/year, we think
that it would be premature to use that information in the ITRF scale definition due to its strong dependence on the GPS satellite
and ground antenna phase center variations. The new position time series also show a better repeatability compared to past
IGS combined products and their annual variations are shown to be more consistent with loading models. The comparison of GPS
station positions and velocities to those of VLBI via local ties in co-located sites demonstrates that the IGS reprocessed
solution submitted to the ITRF2008 is more reliable and precise than any of the past submissions. However, we show that some
of the remaining inconsistencies between GPS and VLBI positioning may be caused by uncalibrated GNSS radomes. 相似文献
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