共查询到19条相似文献，搜索用时 140 毫秒
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在GPS和GLONASS观测方程中考虑硬件延迟偏差的基础上,推导了GPS/GLONASS双系统组合精密单点定位的数学模型,并分析了硬件延迟偏差对估计的未知参数的影响。利用IGS跟踪站的观测数据和动态实验数据,对组合GPS/GLONASS精密单点定位模型进行了试算,并与GPS单系统精密单点定位的结果进行了比较。 相似文献
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GPS电离层延迟Klobuchar模型与双频数据解算值的比较与分析 总被引：10，自引：0，他引：10
电离层延迟是影响GPS绝对定位的最主要因素,但由于电离层本身的不稳定性,加上目前对其物理特性的了解还有一定的模糊性,还只能采用精度有限的经验模型对其进行描述.对于GPS实时绝对定位,GPS系统的广播星历提供了Klobuchr模型的8个系数,可以用于单频接收机的电离层延迟改正;对于双频接收机,可以利用L1,L2,C1,P2进行计算得到电离层延迟值,但应考虑到卫星发射信号时产生的两频率间的硬件延迟TGD的影响.本文采用双频伪距求得电离层延迟值,用广播星历中各颗卫星的TGD参数进行改正,再根据L1和L2双频相位值求得的历元间的电离层延迟的变化采用Hatch类滤波递推模型对其进行平滑,从而求得较准确的对应于各个历元的电离层延迟值,将其作为真值与Klobuchar模型计算值进行比较,从而研究Klobuchar模型的精度和特点,并与IGS的后处理Klobuchar模型系数求得的电离层结果进行对比分析.对双频数据计算电离层延迟的算法进行详细研究,给出Klobuchar模型的具体计算过程,用位于武汉、北京和上海的IGS跟踪站的观测数据进行实际验证和算例分析,最后给出结论. 相似文献
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硬件延迟是利用GPS进行TEC测量时最大的误差源,其影响可达30多TECU。为获得更准确的绝对TEC数值,必须利用一定的电离层模型计算得出GPS系统硬件延迟。本文为估算利用一个时段内的观测数据计算得出的硬件延迟对后续时段TEC测量的影响,利用IGS网络中60多个数据质量良好的GPS跟踪站数据,对硬件延迟的精度和稳定性进行了研究。结果表明:GPS系统硬件延迟在短期内具有较好的精度和稳定性,但是当发生电离层扰动现象时GPS系统硬件延迟的精度和稳定性会遭到破坏。同时根据GPS系统硬件延迟稳定性的研究成果,本文还提出了一种对太阳耀斑进行预报的观点。 相似文献
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利用CDDIS提供的6个IGS站点2018年高精度对流层天顶延迟(ZTD)参考值,对利用ERA-Interim资料计算的ZTD值进行了精度评估.结果显示,ERA-Interim资料计算的ZTD与IGS提供的ZTD产品相比误差在cm级,不同纬度的计算ZTD及其偏差有不同的季节特征.IGS ZTD和ERA-Interim ZTD分别用于GNSS单点定位改正,伪距结果显示两者改正偏差的差异在亚毫米级,且结果在各个方向都得到了改善,U方向最明显,能达到0.5 m左右. 相似文献
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电离层延迟是影响导航定位精度的最主要因素。北斗卫星导航系统采用Klobuchar模型修正单频接收机用户的电离层延迟误差,对于双频接收机,可以利用不同频率信号的伪距观测数据解算得到电离层延迟值。为比较两种方法在天津地区的电离层延迟修正效果,利用NovAtel GPStation6接收机(GNSS电离层闪烁和TEC监测接收机)采集到的卫星实测数据进行计算。以国际全球导航卫星系统服务组织(IGS)发布的全球电离层格网数据为参考,对两种方法的修正效果进行比较分析。结果表明,在天津地区,利用双频观测值解算电离层延迟比Klobuchar模型计算结果更加精确,且平均每天的修正值达到IGS发布数据的82.11％,比Klobuchar模型计算值高948％ 相似文献
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基于球谐函数模型的GPS差分码延迟估计 总被引：1，自引：0，他引：1
电离层延迟是GNSS观测值中最大的误差源,因此如何利用GNSS观测值确定高精度电离层模型逐渐成为实时导航、定位及大气相关研究的重要内容。在通常采用组合观测值建立模型的方法中,精确估计电离层总电子含量（TEC）的重要误差之一是差分码硬件延迟（DCBs）。为了实时得到P1、P2、C2相互间硬件差分码延迟偏差,本文采用IGS跟踪站的观测数据并利用载波平滑后的差分伪距建立观测方程,对卫星和接收机硬件差分码延迟偏差进行实时解算。经比较模型解算DCB值与IGS最大差异不超过0.8 ns,C1、P1码延迟偏差72%差异值小于0.3 ns,P1、P2的74%差异值小于0.3 ns。 相似文献
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精密单点定位方法估计对流层延迟精度分析 总被引：4，自引：0，他引：4
在简要描述精密单点定位估计天项对流层延迟方法的基础上,分别采用IGS事后产品和实时产品处理了若干IGS跟踪站数据,估计出各站天顶对流层延迟,其中,实时精密卫星星历与钟差处理方案采用事后下栽实时产品、事后模拟实时处理的方式.与IGS结果相比,利用精密单点定位方法,采用IGS事后精密星历与卫星钟差估计的结果无明显的偏差,其精度优于6 mm;采用实时精密卫星星历与卫星钟差模拟估计的结果精度优于20 mm. 相似文献
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M_DCB: Matlab code for estimating GNSS satellite and receiver differential code biases 总被引：6，自引：4，他引：2
Global navigation satellite systems (GNSS) have been widely used to monitor variations in the earth’s ionosphere by estimating total electron content (TEC) using dual-frequency observations. Differential code biases (DCBs) are one of the important error sources in estimating precise TEC from GNSS data. The International GNSS Service (IGS) Analysis Centers have routinely provided DCB estimates for GNSS satellites and IGS ground receivers, but the DCBs for regional and local network receivers are not provided. Furthermore, the DCB values of GNSS satellites or receivers are assumed to be constant over 1?day or 1?month, which is not always the case. We describe Matlab code to estimate GNSS satellite and receiver DCBs for time intervals from hours to days; the software is called M_DCB. The DCBs of GNSS satellites and ground receivers are tested and evaluated using data from the IGS GNSS network. The estimates from M_DCB show good agreement with the IGS Analysis Centers with a mean difference of less than 0.7?ns and an RMS of less than 0.4?ns, even for a single station DCB estimate. 相似文献
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The activities of the Ionosphere Working Group of the International GPS Service (IGS) 总被引：5，自引：2，他引：3
This article is based on a position paper presented at the IGS Network, Data and Analysis Center Workshop 2002 in Ottawa,
Canada, 8–11 April 2002, and introduces the IGS Ionosphere Working Group (Iono_WG). Detailed information about the IGS in
general can be found on the IGS Central Bureau Web page: http://igscb.jpl.nasa.gov. The Iono_WG commenced working in June
1998. The working group's main activity currently is the routine production of ionosphere Total Electron Content (TEC) maps
with a 2-h time resolution and daily sets of GPS satellite and receiver hardware differential code bias (DCB) values. The
TEC maps and DCB sets are derived from GPS dual-frequency tracking data recorded with the global IGS tracking network.
In the medium- and long-term, the working group intends to refine algorithms for the mapping of ionospheric parameters from
GPS measurements and to realize near–real–time availability of IGS ionosphere products. The paper will give an overview of
the Iono_WG activities that include a summary of activities since its establishment, achievements and future plans.
Electronic Publication 相似文献
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YAO Yibin 《地球空间信息科学学报》2007,10(4):240-244
With the daily SINEX files of the IGS, the time series of IGS stations are obtained using an independently developed software under generalized network adjustment models with coordinate patterns. From ... 相似文献
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在北斗导航卫星伪距码偏差特性分析的基础上,建立了倾斜地球同步轨道卫星（IGSO）和中轨卫星（MEO）的伪距码偏差多项式改正模型;并利用星间单差宽巷小数周一致性,分析建立北斗地球同步轨道卫星（GEO）卫星伪距码偏差改正模型。采用武汉大学北斗试验网、中国陆态网络和MGEX网不同位置、不同类型接收机观测数据进行分析验证,结果表明,北斗卫星伪距码偏差特性与观测值频率、卫星类型相关,所有GEO和IGSO卫星变化规律相同,所有MEO卫星变化规律相同,与接收机类型、测站位置和观测时间无关,偏差值大小随卫星高度角变化,其变化规律稳定,可以采用建立的两类改正模型（GEO/IGSO和MEO）进行修正。通过偏差修正后的伪距无电离层组合的残差、双频SPP以及单频PPP三个方面验证了伪距码偏差改正模型的正确性。 相似文献
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IGS测站的非线性变化研究 总被引：1，自引：0，他引：1
基于坐标模式的广义网平差模型，利用IGS发布的对GPS全球站处理后形成的单天解SINEX文件，通过自编软件计算了IGS测站的时间序列，并发现IGS测站存在非线性变化。利用频谱分析方法得出了IGS测站存在年周期或半年周期的变化，同时利用经验模型建立了IGS测站的测站速度函数。指出了仅利用1个线性量估计IGS跟踪站的速度值会存在偏差，应建立周期性变化模型，或采用分段线性化的方法，每隔一定的时间给出1个对应的速度。 相似文献
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The ionospheric shell height has an impact on the estimated differential code bias (DCB) and total electron content (TEC) obtained by global navigation satellite system (GNSS) data, especially for a single site. However, the shell height is generally considered as a fixed value. Based on data from the international GNSS service (IGS), we propose the concept of optimal ionospheric shell height, which minimizes |ΔDCB| when compared to the DCB provided by Center for Orbit Determination in Europe (CODE). Based on the data from five IGS stations at high, middle, and low latitudes during the time 2003–2013, we investigate the variation in the optimal ionospheric shell height and its relation with the solar activity. Results indicate that the relation between the mean of the optimal ionospheric shell height and the latitude is N-shaped. At the three stations at midlatitude, the mean value almost increases linearly with the latitude. The optimal ionospheric shell heights show 11-year and 1-year periods. The influences of the solar activity are related to the means of the optimal ionospheric shell height during the time 2003–2013. The slope of the linear fitting decreases with the mean value. Using the data from 2003 to 2013, we estimate the daily optimal ionospheric shell heights for 2014 by using the Fourier fitting method and then calculate the daily average of ΔDCB of the observed satellites by comparing to CODE results. The statistical results of the daily average in 2014 show that the optimal ionospheric shell height is much better than the fixed one. From the high-latitude station to the low-latitude station, the improvements in the mean value are about 75, 92, 96, 50, and 88% and the root-mean-squares are reduced by about 0.16, 2.09, 2.01, 1.01, and 0.02 TECu, respectively. 相似文献
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William G. Kass Robert L. Dulaney Jake Griffiths Stephen Hilla Jim Ray James Rohde 《Journal of Geodesy》2009,83(3-4):289-295
NOAA’s National Geodetic Survey (NGS) has been one of the Analysis Centers (ACs) of the International GNSS Service (IGS) since its inception in 1994. Solutions for daily GPS orbits and Earth orientation parameters are regularly contributed to the IGS Rapid and Final products, as well as solutions of weekly station positions. These solutions are combined with those of the other ACs and then the resultant IGS products are distributed to users. To perform these tasks, NGS has developed and refined the Program for the Adjustment of GPS EphemerideS (PAGES) software. Although PAGES has continuously evolved over the past 15 years, recent efforts have focused mostly on updating models and procedures to conform more closely to IGS and the International Earth Rotation Service (IERS) conventions. Details of our processing updates and demonstrations of the improvements will be provided. 相似文献
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在分析传统GPS/GLONASS组合PPP数学模型中忽略GLONASS码IFB不足的基础上,提出一种基于"多参数"的组合PPP与码IFB估计算法。将"频间偏差"与"系统时差"参数进行合并,通过引入多个独立的"时频偏差"参数对组合PPP中的GLONASS码IFB进行函数模型补偿,同时可实现基于单个测站观测数据的码IFB精确估计。对配备6种GNSS品牌接收机的30个IGS站实测数据进行GLONASS码IFB估计与分析。结果表明:各品牌接收机不同频率通道的GLONASS码IFB可达数米,且表现出与频率的明显相关性,但难以通过简单函数建模为其提供精确的先验改正值;相同品牌接收机的GLONASS码IFB整体上具有相似的特性,而在个别测站会表现出异常特征;即使接收机类型、固件版本及天线类型完全相同的测站,GLONASS码IFB值也可能存在显著差异。新算法能实现对GLONASS码IFB的有效补偿,明显加快组合PPP的收敛速度。虽然引入多个附加参数会导致函数模型自由度减小,但对定位精度的影响有限,与传统"单参数"法进行组合PPP的定位精度相当。 相似文献