共查询到18条相似文献，搜索用时 281 毫秒
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利用GAMIT软件对北京市GPS形变监测网的2004年6月6日到6月12日的数据进行了处理,在处理过程中,对IGS站的选取分了4种情况:①选取13个IGS站;②选取10个IGS站;③选取6个IGS站;④选取1个IGS站。并对4种情况得出的结果从基线重复率WRMS、基线分量的偏差、标准化均方根差NRMS进行了比较,得出以下结论:对于100km内的小区域GPS形变监测网,使用GAMIT软件处理GPS观测数据,最好选取IGS站为区域网提供参考框架;同时对小区域的GPS形变监测网选取6个IGS站就比较合适,解算结果的精度可以达到监测地壳形变的要求;IGS站并不是数量上一定要多,但空间分布要尽量均匀,测站的近似坐标尽量准确。 相似文献
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利用teqc软件对JLCORS网络系统的49个连续运行观测站的观测数据质量进行全面的检测与评估,包括数据完整性、电离层延迟及变率、多路径效应等,数据采样率选用30秒,卫星截止高度角为10度。结果显示,95%的观测站采样效率分布在0.9~1之间,80%的观测站CSR值分布在0.0~0.35之间;所有站点多路径MP1、MP2指标的RMS在0.15~0.45 m范围内,网络系统内MP1、MP1的最大值分别是SLAN站0.45 m和DEFN站0.42 m。接收机运行状态良好,观测环境和观测数据质量完全符合《中国地壳运动观测网络技术规程》要求,而且均优于国际IGS站点标准,对于电离层延迟较严重的时段和不健康的卫星进行了统计,可为GNSS后处理提供可靠的依据。 相似文献
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自1995年起,国际南极研究科学委员会（SCAR,the Scientific Committee on Antarctic Research）组织实施全南极国际GPS（Global Positioning System）联测.本文运用GAMIT/GLOBK软件分析了从1997到2004年的SCAR GPS数据和在南极的一些GPS永久跟踪站数据.数据处理分为两步,第一步：运用GAMIT软件进行单天解算,估计站位置、轨道等参数,其数据源主要有以下三类：(1) SCAR GPS观测站;（2）南极的连续跟踪站;（3）南极及其周边的部分IGS站;第二步：运用GLOBK软件加入SOPAC（Scripps Orbit and Permanent Array Center）的全球GPS子网（IGS1、IGS2、IGS3）进行全球网平差解算测站位置和速度.然后,参照地质构造讨论网的形变,分析了南极板块的现今地壳运动.GPS结果显示南极板块的欧拉角速度是0.224(°)/Ma,旋转极的位置为（58.69°N,128.29°W）,这与NNR-NUVEL-1A预测的和一些前期GPS研究的成果有着较大的不同.相对于澳大利亚板块,本文结果同其他模型的旋转角速度相差约0.01(°)/Ma,旋转极的位置相差在4°以内,不同模型之间的差异相对较小.这为描述南极板块运动提供了一个更为精确的新的运动模型. 相似文献
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利用UNAVCO Facility研制的TEQC软件,对长白山天池火山流动GPS观测的15个点3年的观测资料进行了数据预处理,并按照IGS的标准,对数据进行评定。结果表明,经过TEQC软件的预处理,有效地剔除了原始资料中的错误数据,改善观测数据的质量。 相似文献
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为了分析电离层处理模式对高精度GPS数据处理精度的影响,文中结合全球分布的国际GPS服务(International GPS Service,IGS)跟踪站及具体的工程实例,对不同长度基线进行了处理,结果表明:使用高阶电离层模型改正,对成果精度有一定的提高,特别是不同长度基线处理时,应采用不同的处理模式,以便于保证成果的准确性.针对高精度GPS数据处理需要多时段重复观测的问题,本文基于误差理论提出了GPS数据处理过程中合理构建基线处理回数,多回基线组合平差的新方法;设计典型的实验研究了不同星历条件下长基线的处理效果.成果展示:采用长基线处理回数组合平差的方法,对数据处理成果精度的提高具有显著的效果,且在几种精密星历下均表现良好的收敛性;短基线通过增加基线处理回数及组合平差,成果精度及可靠性进一步提高. 相似文献
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R. Orús M. Hernndez-Pajares J. M. Juan J. Sanz M. García-Fernndez 《Journal of Atmospheric and Solar》2002,64(18)
The existence of a worldwide international GPS service (IGS) permanent network of dual-frequency receivers makes the computation of global ionospheric maps (GIMs) of total electron content (TEC) feasible. The GIMs computed by the IGS Associate Analysis Centers on a daily basis and by other kinds of forecast GIMs, which can be computed from, for instance, the international reference ionosphere (IRI) model, and the GPS broadcast models in the navigation message, can be applied to a broad diversity of fields, for instance as, navigation and time transfer.In this context, the performance of different kinds of models are presented in order to determine the accuracy of the different GIM. This is carried out by comparison with the TOPEX data that provides an independent and precise (at the level of few TECU) vertical TEC determination over the oceans and seas. Thus, the obtained accuracies, in terms of global relative error, ranging from 54% corresponding to the GPS broadcast model, to about 41% corresponding to IRI climatological model, and to less than 30% corresponding to GPS data driven models. 相似文献
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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. 相似文献
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Dual-frequency global navigation satellite systems (GNSS) observations provide most of the input data for development of global ionosphere map (GIM) of vertical total electron content (VTEC). The international GNSS service (IGS) develops different ionosphere products. The IGS tracking network stations are not homogeneously distributed around the world. The large gaps of this network in Middle East, e.g., Iran plateau, reduce the accuracy of the IGS GIMs over this region. Empirical ionosphere models, such as international reference ionosphere (IRI), also provide coarse forecasts of the VTEC values. This paper presents a new regional VTEC model based on the IRI 2007 and global positioning system (GPS) observations from Iranian Permanent GPS Network. The model consists of a given reference part from IRI model and an unknown correction term. Compactly supported base functions are more appropriate than spherical harmonics in regional ionosphere modeling. Therefore, an unknown correction term was expanded in terms of B-spline functions. The obtained results are validated through comparison with the observed VTEC derived from GPS observations. 相似文献
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《Journal of Atmospheric and Solar》2007,69(12):1312-1330
The aim of this study is to assess the availability and quality of data from the International GNSS Service (IGS) Global Positioning System (GPS) network in Africa, especially for retrieving zenith tropospheric delay (ZTD), from which precipitable water vapour (PWV) can be derived, in view of application to the African Monsoon Multidisciplinary Analysis (AMMA) project. Three major error sources for the GPS data analysis evaluating PWV in Africa are the accuracy of the satellite orbits, the correction for the radio delay induced by the ionosphere and the vertical site displacements due to ocean loading. The first part of this study examines these error sources and the validity of GPS data for meteorological applications in Africa in dedicated analyses spanning the year 2001. These analyses were performed using the IGS precise orbits. Weak degradation of baseline precision with increasing baseline lengths suggests that the average orbital error is not limiting the GPS analysis in Africa. The impact of the ionosphere has been evaluated during a maximum of solar activity in 2001. The loss of L2 data has actually been observed. It amounts to 2% on average for 2001, with maxima of 8% during magnetic storm events. A slight decrease in formal accuracy of ZTD seems to be related to the loss of L2 data at the end of the day. This indicates that scintillation effects are present in the GPS observations but however are not a major limitation. The impact of ocean loading is found to be significant on ZTD estimates (up to ±2 mm in equivalent PWV). The use of a proper ocean loading model eliminates this effect.The second aspect of this study concerns the IGS analysis quality for the African stations. The accuracy has been assessed through position dispersion between individual solutions and the most recent version of the IGS combined solution IGb00, and residuals from the transformation of the IGS combined solution into the International Terrestrial Reference Frame 2005. The positioning performance of the IGS analysis is consistent with an accuracy in ZTD of ±6 mm (±1 mm in PWV), as requested for meteorological applications such as planned in AMMA. 相似文献
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Crustal motion of Chinese mainland monitored by GPS 总被引：11，自引：0，他引：11
ZHU Wenyao WANG Xiaoya CHENG Zongyi XIONG Yongqin ZHANG Qiang YE Shuhua MA Zongjin CHEN Junyong XU Houze WEI Ziqing LAI Xi'an LIU Jingnan JIN Biaoren REN Jinwei WANG Qi 《中国科学D辑(英文版)》2000,43(4):394-400
To measure and monitor the crustal motion in China, a GPS network has been established with an average side length of 1 000 km and with more than 20 points on the margins of each major tectonic block and fault zone in China. Three campaigns were carried out in 1992,1994 and 1996, respectively by this network. Here we present, for the first time, the horizontal displacement rates of 22 GPS monitoring stations distributed over the whole China and global IGS stations surrounding China, based on these GPS repeated measurements. From these results by GPS, we have obtained the sketch of crustal motion in China. 相似文献
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从GPS基本观测模型出发,给出并推导了分离相位小数偏差求解非差整数模糊度的精密单点定位数学模型和算法.利用少量IGS跟踪站组成服务端观测网计算未检校的相位小数偏差改正信息,用于改正用户端接收机的相位观测值,实现了固定非差整数模糊度的快速精密单点定位与定轨.试验结果表明: 利用30 min的地面动态或静态观测数据进行精密单点定位,非差模糊度固定成整数后,其定位结果较PPP浮点解有明显改善,水平方向提高了近一个数量级,可达到1 cm甚至毫米级的精度;高程方向与对流层延迟解算精度也改善了20%~60%.与浮点解相比,固定解能显著改善PPP的定轨精度,仅用15 min的短弧段观测数据,切向与法向的定轨精度可达到1 cm左右;径向方向为3~5 cm左右,较浮点解定轨精度改善了50%~70%.因此,固定非差整数模糊度后的PPP能够满足毫米至厘米级的快速精密定位和定轨的要求,这在GPS(准)实时应用与服务中具有很好的应用前景. 相似文献