共查询到19条相似文献,搜索用时 93 毫秒
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讨论了GPS精密单点定位的数学模型。提出了一种改进的GPS精密单点定位算法,该算法是把电离层延迟分为一阶电离层延迟和二阶电离层延迟的方法。分别对各阶电离层进行研究:一阶电离层采用线性组合的方式消除,二阶电离层延迟采用模型估计方法进行消除,最终达到消除电离层影响的目的。最后把该算法应用于GPS/GLONASS组合精密单点定位中,分别从E、N、U 3个定位方向上比较了GPS和GPS/GLONASS组合精密单点定位的定位结果,计算结果表明,该算法在一定程度上提高了定位的精度。较单系统GPS精密单点定位,它能够加快定位的收敛速度,保证定位的连续性。 相似文献
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为了对BDS实时精密单点定位性能进行评估,该文提出了一种适用于BDS系统的实时精密单点定位算法。采用无电离组合模型作为双频实时精密单点定位的数学模型,采用电离层残差法和Melbourne-Wübbena组合实时探测相位周跳,进而单历元实时估计坐标、模糊度等参数,实现了BDS双频实时精密单点定位算法。基于此算法,采用轨道钟差产品和采样间隔为1s的观测数据,模拟实时BDS双频精密单点定位算法,并评估其定位精度。实验结果表明:BDS双频实时定位的平面精度和三维精度均为0.2m左右。 相似文献
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在单频精密单点定位中,电离层延迟是降低定位精度的一个重要因素.本文利用基准站上的双频接收机测定每颗卫星运动轨迹通过电离层的部分,然后通过曲面拟合函数来对各个卫星轨迹通过的电离层建立模型,并对单频精密单点定位进行电离层延迟改正.实验分析表明,用该电离层延迟模型进行单频精密单点定位能够获得较好的精度要求,收敛速度得到了很大的提高. 相似文献
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邰贺 《测绘与空间地理信息》2020,(2):124-127,131
研究利用开源的GNSS数据处理软件GAMP进行精密单点定位解算,阐述了GAMP软件在精密单点定位中使用的数据预处理方法以及电离层、对流层、频间偏差等误差项的改正方法,设计了精密单点定位的解算策略并配置了相关的软件关键参数,对IGS跟踪站jfng站的实测数据进行了解算。结果表明,利用GAMP软件,利用适当的解算策略处理静态数据,约10 min可收敛至亚米级,3 h左右可收敛至厘米级,经过全天的解算其最终精度可达近毫米级。 相似文献
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N. Jakowski 《GPS Solutions》2005,9(2):88-95
The GPS radio occultation technique is a rather simple and inexpensive tool for getting information about the global characteristics of the vertical electron density distribution. No other ionospheric sounding technique (bottomside/topside vertical sounding, incoherent scatter) unifies vertical profiling through the entire ionosphere with global coverage. The paper addresses retrieval methods and algorithms applied for the generation of operational products including their limitations in accuracy and spatial resolution. Preliminary results of ionospheric radio occultation (IRO) measurements carried out onboard the German CHAMP satellite are reported. The achieved accuracy of the retrieved electron density profiles (EDPs) is estimated in particular by comparing the IRO results with independent vertical sounding data from European stations. It is concluded that CHAMP-IRO measurements have the potential to establish global data sets of EDPs, contribute to ionospheric research, develop and improve global ionospheric models and to provide operational space weather information. 相似文献
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结合了圆迹SAR(CSAR)和地球同步轨道SAR(GEOSAR)的特点,地球同步轨道圆迹SAR(GEOCSAR)具有大面积区域观测、可获得目标三维信息、可对目标区域连续监测等优点。但GEOCSAR合成孔径时间长,完成整个圆周孔径测量的时间为24小时,而大气变化的时间尺度经常表现为数分钟到数小时,因此大气折射率时间变化将会对GEOCSAR方位向聚焦成像产生重要影响。本文考虑L波段GEOCSAR,因此对流层和电离层效应均不可忽略。文中建立了对流层和电离层折射率时间变化引起的相位误差模型,分析和推导了折射率时间变化对GEOCSAR方位向聚焦性能的影响,计算了引起L波段GEOCSAR聚焦性能退化的最小对流层折射率和电离层电子含量随机时间变化量,并通过仿真进行了验证。 相似文献
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Ionospheric electron density observed by FORMOSAT-3/COSMIC over the European region and validated by ionosonde data 总被引:4,自引:0,他引:4
Andrzej Krankowski Irina Zakharenkova Anna Krypiak-Gregorczyk Irk I. Shagimuratov Pawel Wielgosz 《Journal of Geodesy》2011,85(12):949-964
This research is motivated by the recent IGS Ionosphere Working Group recommendation issued at the IGS 2010 Workshop held
in Newcastle, UK. This recommendation encourages studies on the evaluation of the application of COSMIC radio occultation
profiles for additional IGS global ionosphere map (GIM) validation. This is because the reliability of GIMs is crucial to
many geodetic applications. On the other hand, radio occultation using GPS signals has been proven to be a promising technique
to retrieve accurate profiles of the ionospheric electron density with high vertical resolution on a global scale. However,
systematic validation work is still needed before using this powerful technique for sounding the ionosphere on a routine basis.
In this paper, we analyze the properties of the ionospheric electron density profiling retrieved from COSMIC radio occultation
measurements. A comparison of radio occultation data with ground-based measurements indicates that COSMIC profiles are usually
in good agreement with ionosonde profiles, both in the F2 layer peak electron density and the bottom side of the profiles.
For this comparison, ionograms recorded by European ionospheric stations (DIAS network) in 2008 were used. 相似文献
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The FORMOSAT-3/COSMIC mission is a microsatellite mission for weather forecast, climate monitoring, and atmospheric, ionospheric and geodesy research. This mission is a collaborative Taiwan-USA science experiment to deploy a constellation of six microsatellites in low Earth orbits. The mission life is 2 years with a goal of 5 years. The final mission orbit has an altitude of 750–800 km. Each satellite consists of three science payloads: global positioning system (GPS) occultation experiment (GOX) payload, tiny ionospheric photometer (TIP) and tri-band beacon (TBB). The GOX will collect the GPS signals for the study on atmosphere, ionosphere, and geodesy. The TIP and TBB can provide the electron distribution information for ionospheric research. The deployment of the FORMOSAT-3 constellation and the resulting influence on the occultation sounding distributions are reported. Details are also given on GOX, TIP, and TBB payload operations and the contributions of the Taiwan Science Team. 相似文献
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Quality assessment of GPS rapid static positioning with weighted ionospheric parameters in generalized least squares 总被引:3,自引:2,他引:1
Pawel Wielgosz 《GPS Solutions》2011,15(2):89-99
Precise GPS positioning requires the processing of carrier-phase observations and fixing integer ambiguities. With increasing
distance between receivers, ambiguity fixing becomes more difficult because ionospheric and tropospheric effects do not cancel
sufficiently in double differencing. A popular procedure in static positioning is to increase the length of the observing
session and/or to apply atmospheric (ionospheric) models and corrections. We investigate the methodology for GPS rapid static
positioning that requires just a few minutes of dual-frequency GPS observations for medium-length baselines. Ionospheric corrections
are not required, but the ionospheric delays are treated as pseudo-observations having a priori values and respective weights.
The tropospheric delays are reduced by using well-established troposphere models, and satellite orbital and clock errors are
eliminated by using IGS rapid products. Several numerical tests based on actual GPS data are presented. It is shown that the
proposed methodology is suitable for rapid static positioning within 50–70 km from the closest reference network station and
that centimeter-level precision in positioning is feasible when using just 1 min of dual-frequency GPS data. 相似文献
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基于非差非组合PPP-RTK的大气改正模型及其性能验证 总被引:2,自引:3,他引:2
高精度的大气改正是加快PPP-RTK收敛的重要前提。本文以区域跟踪网台站数据为基础,基于非差非组合PPP提取斜路径电离层和天顶对流层延迟,作为PPP-RTK大气建模的数据源。电离层延迟采用基于斜路径星间单差的改正模型,对流层采用非差天顶对流层模型,设计了相关的服务端和用户端软件系统。在系统设计上,通过服务端提取数据构建大气模型并播发,用户端接收参数并用于实时PPP-RTK定位。对上海区域进行服务端和用户端的试验,服务端计算的参数表明:GPS、GALILEO、BDS系统的电离层、对流层模型内符合精度为6~7 mm。用户端的646组PPP-RTK伪动态试验表明:水平方向30 s内收敛的占比为89.16%、1 min内收敛的占比为91.80%、2 min内收敛的占比为95.98%;三维方向收敛结果中,上述收敛时间尺度分别占总数的86.22%、88.70%和93.34%。附加大气约束后,模糊度固定率为95.59%,收敛后水平方向和三维方向定位RMSE分别为2.35和4.63 cm。实时动态试验表明,PPP首次固定时间为36 s,水平和三维定位精度分别达到了1.13和3.21 cm。 相似文献
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GPS/BDS中长距离RTK定位因为电离层和对流层残余误差的影响,其性能相对于常规RTK有所降低。将GPS/BDS卫星双差电离层误差和对流层误差作为参数,采用卡尔曼滤波进行实时估计。为了验证算法的有效性,利用武汉地区103 km静态基线24 h双频观测数据,分析了GPS和BDS单系统以及二者组合双系统中长距离RTK定位性能。实验结果表明,精确估计的双差电离层残余误差达到米级、对流层误差达到分米级;经过改正后,GPS/BDS单系统的定位精度在1 cm左右,组合双系统则实现了中长距离基线毫米级的高精度定位。 相似文献