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1.
噪声分析对GPS时间序列分析有着重要影响,然而针对时间跨度较长的大尺度GPS网的共模误差相关研究较少。本文选取了平均基线长度大于2000 km的欧洲地区9个GPS台站2006-2014年的数据,使用主成分分析法剔除坐标时间序列的共模误差,同时利用极大似然估计的方法对滤波前后的时间序列进行了噪声分析。结果表明,欧洲地区广域GPS网的噪声模型存在多样性,各个分量具有不同的噪声特性,主要表现为白噪声+闪烁噪声、白噪声+幂率噪声,少部分台站N、E两个方向含有随机漫步噪声。经过空间滤波后,部分台站最优噪声模型发生改变,但仍以白噪声+闪烁噪声、白噪声+幂率噪声为主。滤波对N、E方向速度场影响为0.2 mm/a,U方向速度场影响为0.5 mm/a。 相似文献
2.
CATS: GPS coordinate time series analysis software 总被引：18，自引：4，他引：14
Simon D. P. Williams 《GPS Solutions》2008,12(2):147-153
Over the last 10 years, several papers have established that daily estimates of GPS coordinates are temporally correlated
and it is therefore incorrect to assume that the observations are independent when estimating parameters from them. A direct
consequence of this assumption is the over-optimistic estimation of the parameter uncertainties. Perhaps the perceived computational
burden or the lack of suitable software for time series analysis has resulted in many heuristic methods being proposed in
the scientific literature for estimating these uncertainties. We present a standalone C program, CATS, developed to study
and compare stochastic noise processes in continuous GPS coordinate time series and, as a consequence, assign realistic uncertainties
to parameters derived from them. The name originally stood for Create and Analyze Time Series. Although the name has survived,
the creation aspect of the software has, after several versions, been abandoned. The implementation of the method is briefly
described to aid understanding and an example of typical input, usage, output and the available stochastic noise models are
given. 相似文献
3.
GPS坐标时间序列中不仅包含白噪声,还包含闪烁噪声、随机漫步噪声等有色噪声,这些噪声将影响GPS应用的可靠性,甚至可能对一些地球物理现象做出错误的解释,因此降低GPS坐标时间序列中有色噪声的影响、提高GPS精度是一个重要和基本的问题。提出了一种滑动L2优化估计方法(ML2),通过选取合适的窗口建立L2优化模型,再利用交替迭代乘子法求解每段时间序列的优化问题,并逐年滑动得到整段GPS坐标时间序列的估计。实验结果表明,ML2方法与奇异谱分析、小波分解、滑动普通最小二乘法相比具有更好的重构效果。 相似文献
4.
时间序列分析及其在测绘领域的应用初探 总被引：2，自引：0，他引：2
时间序列分析是通过对研究对象随时间变化的过程来反映其变化规律并进行预测和分析。目前时间序列分析在统计、金融、贸易等学科领域应用较多,但在测绘领域的应用才刚刚开始。本文对时间序列的基本概念、常用建模方法等进行了概要总结和描述,并通过一个SPSS(Statistical Productand Service Solution,统计产品和服务解决方案)实例的分析,显示时序分析模型的应用过程,对时间序列分析在测绘领域的应用潜力进行了初步探索,为今后的深入研究积累了一定的经验。 相似文献
5.
采用GPS监测运营期大跨度桥梁时,受到交通载荷和观测噪声的影响,GPS监测序列中的振动信号(mm级)完全被湮没,如何从监测序列中提取桥梁变形信息及其振动特性是桥梁健康检测的重要内容。文中利用EMD方法对GPS监测序列进行处理,得到一定数量的本征模态函数(IMF),选取特定的IMF做信号重构和功率谱分析,得到桥梁变形信息和振动特性,相较于传统FFT方法,能准确识别结构振动频率,同时提取变形特征。 相似文献
6.
The International Atomic Time scale (TAI) is computed by the Bureau International des Poids et Mesures (BIPM) from a set of
atomic clocks distributed in about 40 time laboratories around the world. The time transfer between these remote clocks is
mostly performed by the so-called GPS common view method: The clocks are connected to a GPS time receiver whose internal software
computes the offsets between the remote clocks and GPS time. These data are collected in a standard formal called CCTF. In
the present study we develop both the procedure and the software tool that allows us to generate the CCTF files needed for
time transfer to TAI, using RINEX files produced by geodetic receivers driven by an external frequency. The CCTF files are
then generated from the RINEX observation files. The software is freely available at ftp://omaftp.oma.be/dist/astro/time/RINEX_CCTF.
Applied to IGS (International GPS Service) receivers, this procedure will provide a direct link between TAI and the IGS clock
combination. We demonstrate here the procedure using the RINEX files from the Ashtech Metronome (ZXII-T) GPS receiver, to
which we apply the conventional analysis to compute the CCTF data. We compared these results with the CCTF files produced
by a time receiver R100-30T from 3S-Navigation. We also used this comparison with the results of a calibrated time receiver
to determine the hardware delay of the geodetic receiver. ? 2001 John Wiley & Sons, Inc. 相似文献
7.
An acquisition method is proposed which saves processing time and rapidly finds the Global Positioning System (GPS) satellite
with high receiving power. The idea is to combine two or more Coarse/Acquisition (C/A) codes to process acquisition, thus
called “multi-C/A code acquisition method.” The proposed method will change the procedure of conventional Fast Fourier Transform
acquisition slightly, and it has the capabilities to combine with other acquisition methods to perform signal acquisition
simultaneously. In order to show how this multi-C/A code acquisition method may improve the Time To First Fix at the cold
start, the real raw Intermediate Frequency data from a GPS software receiver are used to validate this multi-C/A code acquisition
method. The results show that this method can save at least 23% processing time and it is able to detect the satellite more
rapidly. 相似文献
8.
9.
黄土台塬由于经常性的农业灌溉容易造成边缘区域滑坡发育。因此,需要利用有效手段对这些潜在的滑坡隐患进行早期识别与监测。利用时间序列合成孔径雷达干涉测量（interferometric synthetic aperture radar,InSAR）技术对2016-01至2018-08期间获取的升降轨Sentinel-1数据集进行分析,获取了甘肃永靖黑方台典型台塬地区的滑坡隐患分布情况。将InSAR结果与GPS观测资料进行对比,验证了时序InSAR处理方法的有效性。对该地区滑坡的历史变形分析表明,持续的农业灌溉引起的地下水位抬升是台塬边缘坡体失稳的主要诱因。同时,InSAR时序分析发现,研究区域内的跨黄河大桥受季节更替和温度波动的影响,存在周期性变形现象。实验结果证明了时序InSAR方法在地表变形监测中的有效性,可在黄土滑坡识别与监测防治中发挥重要作用。 相似文献
10.
A global positioning system (GPS)-based online control and alarm system (GOCA) for monitoring of three-dimensional movements
has been developed at the Karlsruhe University of Technology. The GOCA hardware consists of an array of GPS sensors and communication
units to be placed in the monitoring area. The hardware-dependent control software communicates with the GPS sensors and provides
the GPS baseline data and covariance information to the GOCA deformation analysis software. The GOCA center, which comprises
both the control software and the GOCA software, may be linked – for example, over a long distance – to another personal computer
(PC) that serves as a remote control station. GOCA is able to provide the full capabilities of classical deformation analysis
online (with stations grouped into stable points and moving object points). Both types of points may be occupied either continuously
or over short periods at different times. The object points are determined with respect to the stable points. A network adjustment
is performed for each interval of data collection, and the coordinate and covariance information may optionally be transformed
into a specific reference system (e. g., the building system). Unstable reference points are to be detected by statistical
tests. The estimated object point time series are filtered with respect to gross errors using robust estimation techniques.
Online filters are used to smooth the time series data of critical displacements and to predict other deformation functions.
The time series data, as well as prediction results, are displayed graphically for each object point. An example concerning
the online monitoring of a slag heap in a coal-mining area is included. ? 2000 John Wiley & Sons, Inc. 相似文献
11.
The analysis of Global Positioning System (GPS) coordinates time series is a valuable tool in quantifying crustal deformations. The longer continuous GPS time series allow estimation of nonlinear signatures. As a matter of fact, besides the linear and periodic behaviors, other relevant signals are present in such time series as the so-called transient deformations. They can be related to, e.g., slow slip events, which play a crucial role in studying fault mechanisms. To give reliable estimates of these signals, an appropriate and rigorous approach for defining the deterministic and the stochastic models of the data is needed. We prove that the theory of the second order stationary random process (SOSRP) can be used to describe the stochastic behavior of the daily GPS time series. In particular, the second order stationarity condition has to be verified for the daily GPS coordinate time series to be described as a SOSRP. This method has been already used for modeling the gravity field of the earth and in predicting/filtering problems, and this work shows that it can also be useful for characterizing the colored noise in the GPS time series. 相似文献
12.
iGPS: IDL tool package for GPS position time series analysis 总被引：4，自引：3，他引：1
Yunfeng Tian 《GPS Solutions》2011,15(3):299-303
A new tool package written in Interactive Data Language (IDL) was developed for processing and analyzing daily continuous
GPS position time series. This software package can read continuous GPS position time series in various formats, detect outliers,
remove abnormal observation spans, locate epochs of offsets or post-seismic relaxation events, and estimate their amplitudes.
It also provides functionalities for epoch statistics, site selection, periodic noise analysis, spatial filtering (by regional
stacking), etc. This tool is referred to as iGPS. 相似文献
13.
Maryam Dehghani Mohammad Javad Valadan Zoej Sassan Saatchi Juliet Biggs Barry Parsons Tim Wright 《Journal of the Indian Society of Remote Sensing》2009,37(1):147-156
A large agricultural area located in 20 km north of the city of Mashhad in the north-east of Iran is subject to land subsidence.
The subsidence rate was achieved in a couple of sparse points by precise leveling between 1995 and 2005, and continuous GPS
measurements obtained from 2005 to 2006. In order to study the temporal behavior of the deformation in high spatial resolution,
the small baseline subset (SBAS) algorithm was used to generate the interferometric SAR time series analysis. Time series
analysis was performed using 19 interferograms calculated from 12 ENVISAT ASAR data spanning between 2003 and 2006. The time
series results exhibited that the area is subsiding continuously without a significant seasonal effect. Mean LOS deformation
velocity map obtained from time series analysis demonstrated a considerable subsidence rate up to 24 (cm/yr). In order to
evaluate the time series analysis results, continuous GPS measurements as a geodetic approach were applied. The comparisons
showed a great agreement between interferometry results and geodetic technique. Moreover, the information of various piezometric
wells distributed in the area corresponding to 1995 to 2005 showed a significant decline in water table up to 20 meters. The
correlation between the piezometric information and the surface deformation at well’s locations showed that the subsidence
occurrence in Mashhad is due to the excess groundwater withdrawal. 相似文献
14.
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
15.
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
16.
17.
利用时间序列分析预报电离层TEC 总被引：5，自引：2，他引：3
以IGS发布的电离层总电子含量(total electron content,TEC)数据为样本,利用时间序列分析进行预报。将TEC时间序列分解为趋势项、周期项和随机项的组合,并利用相关系数和偏相关系数确定模型阶数。对IGS提供的2008年TEC数据进行预报分析,结果表明,采用时间序列分析能达到较高精度,预报7 d时的平均相对精度为87.75%,预报精度大于60%的预报值占所有预报值的95%以上,预报精度大于85%的预报值占所有预报值的72.6%,95.3%的预报残差小于±3 TECU。 相似文献
18.
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
19.
We compare two methods for monitoring the dynamic response of tall buildings to wind loading, using data from a 280-m-high
building in Singapore. The first method is based on accelerometer measurements. The second method is based on the Global Positioning
System (GPS) technology. The GPS can in principle detect absolute displacements with lower frequencies than the accelerometers,
but the GPS positioning signal is usually very noisy. We propose a systematic procedure for modeling the stochastic and systematic
components of the GPS displacement time series and for extracting the weak structural response from the dominant noise. The
spectrum of the building response obtained from the filtered GPS data exhibits a dominant peak at 0.19 Hz. The frequency of
the peak coincides with that obtained from the analysis of the accelerometer data. The proposed analysis of the GPS signal
provides a method for cross-validating the GPS and accelerometer measurements, and shows that “educated” filtering of the
GPS signal can reveal essential features of the building’s response to wind loading. 相似文献