共查询到19条相似文献，搜索用时 156 毫秒
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基于MODIS与GPS的D-InSAR大气延迟改正量提取 总被引：1，自引：0，他引：1
受GPS站点密度的限制,利用GPS数据改正D-InSAR中大气延迟误差往往达不到很好的效果。为此,研究了GPS与MODIS联合实现大气延迟改正量提取方法,利用两期GPS观测数据及相应时间的MODIS数据分析GPS-PWV与MODIS-PWV的关系,进一步得到MODIS水汽的校正模型。经过GPS+MODIS算法改正后,大气延迟改正精度为3.618mm,满足形变测量的要求。实验结果表明:在大气状态变化缓慢时,利用GPS结合MODIS数据对D-InSAR大气延迟改正有一定的效果。 相似文献
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《测绘与空间地理信息》2020,(7)
随着地面沉降监测手段日益丰富,对多源地面沉降监测数据进行数据融合逐渐成为研究的热点。本文针对大气延迟对InSAR地面沉降监测的影响,利用GPS获取对流层延迟,对不同的内插模型,讨论了Kriging内插法、IDW内插法对流层延迟改正的内插模型,并在IDW内插法的基础上进行改进,提出了IIDW内插法,采用香港GPS监测数据与哨兵一号雷达卫星监测数据,通过3种内插模型,得到不同内插方法的双差分结果,并分析比较了3种内插方法的优劣。用计算出的差分对流层延迟改正对InSAR影像进行改正。实验结果表明:IIDW内插法对对流层延迟进行改正不仅提高了D-InSAR的精度,而且为InSAR与GPS数据融合解决提供了一种新的思路。 相似文献
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在InSAR大气延迟改正双差模型的基础上,推导了适用于三归法D-InSAR测量的大气延迟改正模型。利用新西兰GEONET北岛连续观测GPS数据,研究了多雨山区InSAR对流层延迟内插模型。 相似文献
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InSAR大气水汽改正模型的比较应用研究 总被引：3，自引：1，他引：2
对基于GPS数据的大气水汽扰动模型(GPS topography-dependent turbulence model,GTTM)和GPS/MODIS集成的大气水汽改正模型进行了比较研究.试验证明,GTTM模型和GPS/MODIS集成模型的改正方法都可以大大降低大气水汽对InSAR测量地面形变量精度的影响.另外,当两种模型都用于改正InSAR观测值时,它们具有很强的互补性. 相似文献
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不同空间插值对InSAR大气延迟改正影响研究 总被引：2，自引：0，他引：2
大气效应是InSAR技术用于地表探测的主要误差源之一。GPS数据作为InSAR大气延迟误差改正的重要数据源,受其站点分布疏密的影响,分辨率还无法做到与SAR影像完全相匹配,必须对GPS获取的大气延迟数据进行空间插值。本文采用反距离加权法(IDW)、Kriging插值法和移动曲面拟合法(Surface Moving Fitting,SMF)三种插值方法,探讨了InSAR大气误差改正过程中的空间插值问题,并对三种插值的精度进行了分析和评价。 相似文献
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电离层延迟误差是单频GPS实时/事后定位误差的一个重要来源,目前尚无有效的方法来削弱其影响。针对这一状况,该文首先介绍了单频GPS改正电离层延迟误差的常用方法,通过分析说明了电离层格网数据能够有效改善单频GPS实时/事后定位误差。给出了电离层格网数据的建立、预报方法,并详细介绍了刺入点地心经纬度VTEC值的计算方法、四点格网法内插刺入点天顶方向的总电子含量以及单层模型投影函数。结合算例,分析比较了不同类型电离层改正数据与卫星星历数据对单频GPS实时/事后定位精度的影响。实验结果表明,利用电离层格网预报数据能够显著改善单频GPS的实时/事后导航定位精度,对提高单频GPS定位精度具有一定实用价值。 相似文献
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《北京测绘》2017,(Z1)
电离层延迟是限制GNSS定位精度的主要误差源之一,采用合理的电离层改正模型能够削弱定位误差。本文对Klobuchar模型、GIM模型以及NTCM-BC模型的原理进行了阐述,并以九峰台站2016-01-07~2016-01-09观测数据为对象,从不同的角度对BDS K8、GPS K8、GIM和NTCM-BC电离层模型对单点定位的精度的改正效果进行了分析。实验结果表明,九峰台站处,GPS K8和BDS K8模型改正后的单点定位误差RMS分别为2.8553m和1.7932m,NTCM-BC模型改正后的单点定位误差RMS为1.7290m,GIM模型改正后的单点定位误差RMS为1.2834m。 相似文献
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Analysis of tropospheric delay prediction models: comparisons with ray-tracing and implications for GPS relative positioning 总被引：2，自引：0，他引：2
Ray-tracing is used to examine the accuracy of several well known models for tropospheric delay prediction under varying atmospheric conditions. The models considered include the Hopfield zenith delay model and related mapping functions, the Saastamoinen zenith delay model and mapping function, and three empirical mapping functions based upon the Marini continued fraction form. Modelled delays are benchmarked against ray-tracing solutions for representative atmospheric profiles at various latitudes and seasons. Numerical results are presented in light of the approximations inherent in model formulation. The effect of approximations to the temperature, pressure and humidity structure of the neutral atmosphere are considered; the impact of surface layer anomalies (i.e., inversions) on prediction accuracy is examined; and errors resulting from the neglect of ray bending are illustrated. The influence of surface meteorological parameter measurement error is examined. Finally, model adaptability to local conditions is considered. Recommendations concerning the suitability of the models for GPS relative positioning and their optimal application are made based upon the results presented. 相似文献
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GPS定位中的对流层模型分析 总被引：1，自引：0，他引：1
系统地分析对流层延迟特性在GPS导航中造成的定位误差,并主要介绍目前卫星定位领域主要应用的一些对流层折射修正模型。基于霍普尔德模型和萨斯塔莫宁模型,提出一种在缺少实测气象参数条件下,使用的简单对流层延迟修正模型。利用Matlab仿真软件对静态和动态接收机实测数据进行分析。结果表明,无气象参数的简单修正模型可以消除70％左右的对流层影响,有效地提高GPS的定位精度。 相似文献
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Petr Vaníček Richard B. Langley David E. Wells Demitris Delikaraoglou 《Journal of Geodesy》1984,58(1):37-52
Differential GPS positioning is considered from the purely geometric point of view. The tetrahedron formed by two ground stations
and two satellite locations is the basic geometrical building block for differential satellite positioning. Relationships
between the various vectors involved in this tetrahedron are described. These relationships are used to develop linear mathematical
models which relate the vector baseline between the two ground stations to various kinds of differential GPS observations.
Geometrically, all proposed observation types can be considered as either differential range observations or differential
range difference observations. In the absence of instrumental and refraction effects, it is found that differential range
observations are geometrically superior to differential range difference observations. Some implications of these geometrical
considerations to practical differential GPS positioning are discussed. 相似文献
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Atmospheric modelling in GPS analysis and its effect on the estimated geodetic parameters 总被引：4，自引：2，他引：2
Permanently operating Global Positioning System (GPS) receivers are used today, for example, in precise positioning and determination
of atmospheric water vapour content. The GPS signals are delayed by various gases when traversing the atmosphere. The delay
due to water vapour, the wet delay, is difficult to model using ground surface data and is thus often estimated from the GPS
data. In order to obtain the most accurate results from the GPS processing, a modelling of the horizontal distribution of
the wet delay may be necessary. Through simulations, three such models are evaluated, one of which is developed in this paper.
In the first model the water vapour is assumed to be horizontally stratified, thus the wet delay can be described by only
one zenith parameter. The second model gives the wet delay with one zenith and two horizontal gradient parameters. The third
model uses the correlation between the wet-delay values in different directions. It is found that for large gradients and
strong turbulence the two latter models yield lower errors in the estimated vertical coordinate and wet-delay parameters.
For large gradients this improvement is up to 7 mm in the zenith wet-delay parameter, from 9 mm down to 2 and 4 mm for the
second and third models, respectively.
Received: 7 May 1998 / Accepted: 1 March 1999 相似文献
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Analyzing GNSS data in precise point positioning software 总被引：4，自引：1，他引：3
This work demonstrates that precise point positioning (PPP) can be used not only for positioning, but for a variety of other
tasks, such as signal analysis. The fact that the observation model used for accurate error modeling has to take into consideration
the several effects present in GPS signals, and that observations are undifferenced, makes PPP a powerful data analysis tool
sensitive to a variety of parameters. The PPP application developed at the University of New Brunswick, which is called GAPS
(GPS Analysis and Positioning Software), has been designed and built in order to take advantage of available precise products,
resulting in a data analysis tool for determining parameters in addition to position, receiver clock error, and neutral atmosphere
delay. These other estimated parameters include ionospheric delays, code biases, satellite clock errors, and code multipath
among others. In all cases, the procedures were developed in order to be suitable for real-time as well as post-processing
applications. One of the main accomplishments in the development described here is the use of very precise satellite products,
coupled with a very complete observation error modeling to make possible a variety of analyses based on GPS data. In this
paper, several procedures are described, their innovative aspects are pointed out, and their results are analyzed and compared
with other sources. The procedures and software are readily adaptable for using data from other global navigation satellite
systems. 相似文献
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对流层延迟是GPS定位的主要误差源之一,一直是高精度GPS定位的障碍。本文针对湿分量延迟计算复杂,影响因素多,经模型改正后也不理想的现实情况,巧妙的使用IGS产品推算对流层延迟湿分量,进一步削弱了GPS定位中对流层延迟的影响,得出了一些有益的结论。 相似文献
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在大气折射延迟模型中避免采用大气分布模型的论证 总被引：2，自引：2，他引：0
天文大气折射是经典天体测量学和大地测量的一项误差源,大气折射延迟是空间大地测量技术中的一项重要误差源,它们的改正模型都直接与大气折射率和大气分布模型有关。文章简述了大气的垂直分布状况,以及大气折射率(或折射率差)因地和因方位而异的情况,分析了目前只能采用球对称大气分布模型的原因。论证了随测站和随方位而异的天文大气折射和电磁波大气折射延迟实测模型建立的必要性和可能性。实测模型已经包含了测站上空大气实际分布及其非球对称的特性,不必再去寻找或建立随地势而异和随季节而变的大气分布模型,避免了大气分布模型选择不当的影响,从而排除了空间大地测量技术中的一项主要误差源。 相似文献