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GAMIT/GLOBK是美国麻省理工学院(MIT)和斯克里普斯海洋研究所(SIO)开发的全球应用最为广泛的GPS分析软件之一,介绍了系统平台SUSE11.1及GAMIT/GLOBK软件的安装及使用方法。该软件的安装及使用方法对LINUX及GAMIT/GLOBK感兴趣的读者具有一定启发与帮助。 相似文献
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GAMIT是国内外高精度GPS数据处理中通常采用的软件之一,多安装于Linux操作系统,本文主要介绍了GAMIT在Linux平台下的安装与使用,并通过算例来说明GLOBK进行网平差后所得到的坐标结果是可靠的。 相似文献
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GAMIT/GLOBK是一套高精度GPS数据处理分析软件,多安装于Linux操作系统。由于Linux版本众多,使得该软件的安装复杂。实践中仍会遇到很多问题。在总结前人安装GAMIT的经验基础上介绍以Ubuntu桌面版构建系统平台,在网络的支持下,安装、更新最新版GAMIT/GLOBK10.40的详细过程,并运行GAMIT检验安装是否成功。 相似文献
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Compared with the traditional GPS L1 C/A BPSK-R(1) signal, wideband global navigation satellite system (GNSS) signals suffer more severe distortion due to ionospheric dispersion. Ionospheric dispersion inevitably introduces additional errors in pseudorange and carrier phase observations that cannot be readily eliminated by traditional methods. Researchers have reported power losses, waveform ripples, correlation peak asymmetries, and carrier phase shifts caused by ionospheric dispersion. We analyze the code tracking bias induced by ionospheric dispersion and propose an efficient all-pass filter to compensate the corresponding nonlinear group delay over the signal bandwidth. The filter is constructed in a cascaded biquad form based on the estimated total electron content (TEC). The effects of TEC accuracy, filter order, and fraction parameter on the filter fitting error are explored. Taking the AltBOC(15,10) signal as an example, we compare the time domain signal waveforms, correlation peaks, code tracking biases, and carrier phase biases with and without this all-pass filter and demonstrate that the proposed delay-equalization all-pass filter is a potential solution to ionospheric dispersion compensation and mitigation of observation biases for wideband GNSS signals. 相似文献
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Application of SWACI products as ionospheric correction for single-point positioning: a comparative study 总被引:1,自引:0,他引:1
In Global Navigation Satellite Systems (GNSS) using L-band frequencies, the ionosphere causes signal delays that correspond with link related range errors of up to 100 m. In a first order approximation the range error is proportional to the total electron content (TEC) of the ionosphere. Whereas this first order range error can be corrected in dual-frequency measurements by a linear combination of carrier phase- or code-ranges of both frequencies, single-frequency users need additional information to mitigate the ionospheric error. This information can be provided by TEC maps deduced from corresponding GNSS measurements or by ionospheric models. In this paper we discuss and compare different ionospheric correction methods for single-frequency users. The focus is on the comparison of the positioning quality using dual-frequency measurements, the Klobuchar model, the NeQuick model, the IGS TEC maps, the Neustrelitz TEC Model (NTCM-GL) and the reconstructed NTCM-GL TEC maps both provided via the ionosphere data service SWACI (http://swaciweb.dlr.de) in near real-time. For that purpose, data from different locations covering several days in 2011 and 2012 are investigated, including periods of quiet and disturbed ionospheric conditions. In applying the NTCM-GL based corrections instead of the Klobuchar model, positioning accuracy improvements up to several meters have been found for the European region in dependence on the ionospheric conditions. Further in mid- and low-latitudes the NTCM-GL model provides results comparable to NeQuick during the considered time periods. Moreover, in regions with a dense GNSS ground station network the reconstructed NTCM-GL TEC maps are partly at the same level as the final IGS TEC maps. 相似文献
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为了分析与评估国际GNSS监测评估系统(iGMAS)全球电离层TEC格网产品精度,该文基于iGMAS及IGS各电离层分析中心发布的全球电离层TEC格网产品,进行了精度比较分析,结果表明:iGMAS与IGS、CODE、JPL、ESOC、UPC等IGS电离层工作组发布的全球电离层TEC格网产品,在全球、不同纬度带和欧洲等不同区域均表现出较高的一致性和强相关性,互差为0~2.0 TECU;JPL分析中心GIM的内符合精度约为2.5 TECU,iGMAS、IGS、CODE、ESOC和UPC等分析中心GIM的内符合精度均小于1.5 TECU;在2~8 TECU的精度范围内,iGMAS全球电离层TEC格网产品的精度总体与IGS、CODE、JPL、ESOC、UPC等IGS电离层工作组的精度相当。 相似文献
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为了分析单站区域电离层总电子含量(total electron content,TEC)模型的适用范围和精度,基于2~15阶次球谐函数,分别建立了欧洲区域16个单站区域电离层TEC模型,生成了区域格网TEC,并与欧洲定轨中心(Center for Orbit Determination in Europe,CODE)、... 相似文献
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Ionospheric correction using NTCM driven by GPS Klobuchar coefficients for GNSS applications 总被引:1,自引:1,他引:0
Global Navigation Satellite Systems (GNSS) require mitigation of ionospheric propagation errors because the ionospheric range errors might be larger than tens of meters at the zenith direction. Taking advantage of the frequency-dispersive property of ionospheric refractivity, the ionospheric range errors can be mitigated in dual-frequency applications to a great extent by a linear combination of carrier phases or pseudoranges. However, single-frequency GNSS operations require additional ionospheric information to apply signal delay or range error corrections. To aid single-frequency operations, the global positioning system (GPS) broadcasts 8 coefficients as part of the navigation message to drive the ionospheric correction algorithm (ICA) also known as Klobuchar model. We presented here an ionospheric correction algorithm called Neustrelitz TEC model (NTCM) which can be used as complementary to the GPS ICA. Our investigation shows that the NTCM can be driven by Klobuchar model parameters to achieve a significantly better performance than obtained by the mother ICA algorithm. Our research, using post-processed reference total electron content (TEC) data from more than one solar cycle, shows that on average the RMS modeled TEC errors are up to 40% less for the proposed NTCM model compared to the Klobuchar model during high solar activity period, and about 10% less during low solar activity period. Such an approach does not require major technology changes for GPS users rather requires only introducing the NTCM approach a complement to the existing ICA algorithm while maintaining the simplicity of ionospheric range error mitigation with an improved model performance. 相似文献
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This research shows the viability of using Global Navigation Satellite System (GNSS) stations from Brazilian active networks in monitoring the ionosphere. Various indexes of ionospheric irregularities and scintillation of GNSS signals, estimated in real-time and post-processed from GNSS data, are explored for this purpose. This way, an increase in the spatial resolution of ionospheric information is provided, allowing the generation of maps of scintillation and irregularities in observing the spatial and temporal behavior of the layer’s activity cycle, since the number of ionosondes, imagers, and radars is insufficient for monitoring the irregularities in Brazil. Experiments to evaluate the estimates of the indexes are performed for periods of high and low variability of electrons. Three Brazilian networks are used: the Brazilian Network for Continuous Monitoring (RBMC), the GNSS Active Network of Sao Paulo State (GNSS-SP), and CIGALA/CALIBRA. The results are compared with data from ionosondes and PolaRxS-PRO Septentrio receivers, proving compatible with moderate to high correlations. An analysis of the seasonal variation during the peak of solar cycle 24 is carried out. The maps allow identifying the displacement of ionospheric irregularities along the magnetic equator over Brazil, from northeast to southwest, starting at 7:00 pm and ending at 2:00 am local time. Real-time monitoring is carried out for the summer solstice in the southern hemisphere, and results are consistent with those from the post-processed mode. The indexes and maps can be applied to the analysis of GNSS positioning. Real-time ionospheric information can be used in important practical applications because the displacement monitoring of irregularities allows prior knowledge of whether there will be a deterioration of positioning accuracy in a certain region. 相似文献
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The ionosphere: effects,GPS modeling and the benefits for space geodetic techniques 总被引:12,自引:8,他引:4
Manuel Hernández-Pajares J. Miguel Juan Jaume Sanz Àngela Aragón-Àngel Alberto García-Rigo Dagoberto Salazar Miquel Escudero 《Journal of Geodesy》2011,85(12):887-907
The main goal of this paper is to provide a summary of our current knowledge of the ionosphere as it relates to space geodetic
techniques, especially the most informative technology, global navigation satellite systems (GNSS), specifically the fully
deployed and operational global positioning system (GPS). As such, the main relevant modeling points are discussed, and the
corresponding results of ionospheric monitoring are related, which were mostly computed using GPS data and based on the direct
experience of the authors. We address various phenomena such as horizontal and vertical ionospheric morphology in quiet conditions,
traveling ionospheric disturbances, solar flares, ionospheric storms and scintillation. Finally, we also tackle the question
of how improved knowledge of ionospheric conditions, especially in terms of an accurate understanding of the distribution
of free electrons, can improve space geodetic techniques at different levels, such as higher-order ionospheric effects, precise
GNSS navigation, single-antenna GNSS orientation and real-time GNSS meteorology. 相似文献
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Experimental analysis was performed using multiplicative algebraic reconstruction technique (MART) to map the ionosphere over Brazil. Code and phase observations from the global navigation satellite system (GNSS) together with the international reference ionosphere (IRI) enabled the estimation of ionospheric profiles and total electron content (TEC) over the entire region. Twenty-four days of data collected from existing ground-based GNSS receivers during the recent solar maximum period were used to analyze the performance of the MART algorithm. The results were compared with four ionosondes. It was demonstrated that MART estimated the electron density peak with the same degree of accuracy as the IRI model in regions with appropriate geometrical coverage by GNSS receivers for tomographic reconstruction. In addition, the slant TEC, as estimated with MART, presented lower root-mean-square error than the TEC calculated by ionospheric maps available from the International GNSS Service (IGS). Furthermore, the daily variations of the ionosphere were better represented with the algebraic techniques, compared to the IRI model and IGS maps, enabling a correlation of the elevation of the ionosphere at higher altitudes with the equatorial ionization anomaly intensification. The tomographic representations also enabled the detection of high vertical gradients at the same instants in which ionospheric irregularities were evident. 相似文献
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Effects of rapidly changing ionospheric weather are critical in high accuracy positioning, navigation, and communication applications. A system used to construct the global total electron content (TEC) distribution for monitoring the ionospheric weather in near-real time is needed in the modern society. Here we build the TEC map named Taiwan Ionosphere Group for Education and Research (TIGER) Global Ionospheric Map (GIM) from observations of ground-based GNSS receivers and space-based FORMOSAT-3/COSMIC (F3/C) GPS radio occultation observations using the spherical harmonic expansion and Kalman filter update formula. The TIGER GIM (TGIM) will be published in near-real time of 4-h delay with a spatial resolution of 2.5° in latitude and 5° in longitude and a high temporal resolution of every 5 min. The F3/C TEC results in an improvement on the GIM of about 15.5%, especially over the ocean areas. The TGIM highly correlates with the GIMs published by other international organizations. Therefore, the routinely published TGIM in near-real time is not only for communication, positioning, and navigation applications but also for monitoring and scientific study of ionospheric weathers, such as magnetic storms and seismo-ionospheric anomalies. 相似文献