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随着全球导航卫星系统（Global Navigation Satellite Systems,GNSS）的不断发展,中国地区单个GNSS接收站在一个时刻可以接收到超过30颗GNSS卫星的信号,这为单站GNSS硬件延迟估算方法的研究提供了有利条件.本文首先通过GNSS硬件实验,分析了不同温度条件下GNSS系统硬件延迟的变化特征,研究结果显示：当温度快速变化时,硬件延迟变化比较剧烈,变化幅度可达12.53 TECU（1 TECU=10 16el·m-2）;在恒温条件或室温条件下,硬件延迟变化比较缓慢,变化幅度在1.00 TECU左右.在GNSS系统硬件延迟实验的基础上,充分利用单站多星观测的特点,提出了一种基于单站多系统的GNSS硬件延迟的估算方法——单站三角分解与差分消元法,并将该方法应用于河北保定站2015-2017年GNSS系统硬件延迟的求解中.通过对估算的GNSS系统硬件延迟进行分析显示：单站三角分解与差分消元法具有计算速度快、独立性好的特点;在北斗系统上硬件延迟的求解效果优于GPS、GLONASS系统,硬件延迟求解的结果整体上比利用欧洲定轨中心全球电离层地图校正的结果大2.50~3.00TECU左右;同时,该方法在消除GNSS系统硬件延迟后,获得的垂直总电子含量（Total Electron Content,TEC）能较好地反映电离层TEC的周日变化、日出增强、半年变化、年变化和春秋分不对称性等特征. 相似文献
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GPS接收机差分码偏差（Differential Code Bias,DCB）是利用COSMIC低轨卫星观测值反演电离层总电子含量TEC的一项重要误差源.本文将COSMIC卫星轨道高度以上的电离层作为一个单层,采用球谐函数来参数化电离层TEC值,并利用最小二乘法同时估算电离层球谐系数和DCB参数.运用这种方法对2012年12月份的所有COSMIC卫星GPS接收机DCB进行了解算,并与COSMIC数据分析与档案中心CDAAC提供的产品进行了比较.实验结果表明：在2012年12月期间,估计的接收机DCB与CDAAC结果符合的较好,二者DCB变化趋势相近,DCB差值的RMS值在2 TECU以内,且最大绝对差值小于3 TECU;此外,本文计算的接收机DCB估计误差主要分布在0.2~0.4 TECU之间,具有较高的内符合精度. 相似文献
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利用GPS计算TEC的方法及其对电离层扰动的观测 总被引：36，自引：8，他引：28
在总结用ＧＰＳ研究电离层电子总量ＴＥＣ的数据处理方法基础上,分析了利用伪距观测量和载波相位观测量计算电离层ＴＥＣ的特点及误差来源．在处理过程中考虑了卫星的硬件延迟偏差,分析了应用ＩＲＩ模型进行接收机硬件延迟偏差修正的可能性,发现利用少量ＧＰＳ数据和ＩＲＩ模型修正接收机硬件延迟偏差有一定的困难．最后,利用一些ＧＰＳ观测数据有针对性地研究了电离层对若干次扰动事件的响应．包括一次大的太阳耀斑期间的电离层ＴＥＣ变化、一次较典型的电离层行扰以及日食期间的电离层ＴＥＣ的相对变化等电离层物理问题．结果表明,利用该方法计算ＴＥＣ的精度可满足电离层扰动现象的研究． 相似文献
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卫星和接收机仪器偏差(Differential Code Biases,DCB)是利用GPS(Global Positioning System)研究电离层的两类主要误差源.由于所处的空间环境恒定,且可被全球跟踪站连续观测,GPS卫星的DCB具备长期稳定性和较高的估计精度.但针对各类型接收机而言,受测站环境、硬件设施等影响,其DCB可能会呈现明显的短期变化.精确地模型化接收机DCB的短期变化特征,将有助于提高GPS电离层产品的可靠性,以及基于这些产品反演空间和地球科学现象的准确性.采用零/短基线GPS数据,本文改进了提取和分析接收机DCB变化的现有方案.随后,本文推导了一种能直接估计接收机DCB的函数模型.当检验出接收机DCB的短期变化服从随机游走时,通过对比接收机DCB的直接估值与间接提取值之间的符合程度,可"试探出"过程噪声标准差的最优经验值.实验分析选用4台双频接收机(共形成1条零基线和2条短基线,间距最大为15m)多天的观测数据,主要结论包括:1)改进的接收机DCB提取方案能较好地克服低频伪距噪声和多路径效应的影响;2)针对零基线,其接收机DCB在各天内的变化量级小于1TECu,变化趋势则可采用过程噪声标准差为1.0~1.5mm的随机游走加以描述;3)对应于某短基线的接收机DCB在某天内的变化可达12TECu,当采用随机游走描述其趋势时,过程噪声标准差的经验值超过2mm. 相似文献
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LEO GPS观测已成为空间电离层研究重要手段之一,通过GPS双频观测值获取的TEC则是电离层探测的一个重要参量,为获取高精度TEC需估计和消除GPS接收机仪器偏差（DCB）.本文旨在探索一种全新的LEO GPS接收机仪器偏差的估计方法：基于电离层球对称的假设,利用CHAMP和COSMIC原始GPS观测数据,采用几何映射函数,通过最小二乘解算出GPS接收机仪器偏差.结果表明：(1)2008年1月份期间,通过上述方法解算的仪器偏差都较稳定,相比COSMIC网上发布结果,标准偏差都在0.6 ns以内;（2）COSMIC（轨道高度大约800 km）仪器偏差估计结果优于CHAMP（轨道高度大约400 km）的结果,原因为：对于不同轨道高度LEO GPS仪器偏差估计,其较高轨道高度的电离层球对称假设影响较小. 相似文献
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首先基于半解析法建立了新的GRACE卫星K波段测量系统星间测速、GPS接收机轨道位置和加速度计非保守力误差联合影响累计大地水准面的误差模型;其次,基于各关键载荷精度指标的匹配关系,论证了误差模型的可靠性;最后,基于美国喷气动力实验室（JPL）公布的2006年的GRACE Level 1B实测误差数据,有效和快速地估计了120阶全球重力场的精度,在120阶处累计大地水准面的精度为18.368 cm,其结果和德国地学研究中心（GFZ）公布的EIGEN-GRACE02S全球重力场模型符合较好. 本文的研究为将来国际卫星重力测量计划（如GRACE Follow-On, 360阶）中高阶全球重力场模型精度的有效和快速估计提供了理论基础和计算保证. 相似文献
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基于四川GPS观测网络,本文提出采用低成本GPS-OEM板设计分米级差分GPS接收机。介绍四川GPS观测网络的工作原理,应用GPS观测网络改正由GPS轨道误差、电离层、对流层和大气折射引起的误差,将高精度的差分信息通过GPRS发给流动站来提高接收机的定位精度;论证了差分GPS的定位原理;最后提出整个系统的设计方案,用Thales DG14L OEM板处理GPS天线接收到的卫星信息,同时对GPRS天线接收数据中心差分信号进行差分运算。单片机控制软件采用汇编语言和C语言来编写。系统的实验结果表明,差分GPS接收机应用效果好,定位精度高,最重要的是降低了接收机的成本。 相似文献
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本文在运用TEQC软件结合QCVIEW32和DOSBox 0.74两款软件对GPS/GLONASS定位数据分析的基础上,引入朱静然等人设计的多系统GNSS数据质量分析软件对Beidou/GPS/GLONASS定位数据进行质量分析,并对北斗卫星(Beidou)、双星(GPS/GLONASS)和多星(Beidou/GPS/GLONASS)定位数据的多路径效应、电离层延迟、数据利用率与信噪比、卫星可见数和精度因子PDOP值等几个方面进行比较分析.试验分析表明:双星系统下的L1、L2两大频率兼容性良好;双星系统下的双频数据质量和稳定性良好,接收机周跳修复能力较强;多星融合的多路径误差明显小于北斗单系统,平均mp1和mp2分别减小了18%和6%,多星融合增加的卫星在一定程度上可以相互补偿从而削弱多路径效应对定位结果的影响;在观测条件复杂,截止高度角较高的情况下,单一系统无法满足高精度定位需求,而组合系统可以保持较低并且变化平缓的PDOP值,提供了高精度的定位服务. 相似文献
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The Global Positioning System (GPS) observables are affected by the ionosphere. The dispersive nature of this effect and the use of two frequencies in the GPS observations make possible to measure the ionospheric total electron content (TEC) from dual frequency GPS data. In this work we test the concept of permanent monitoring of TEC using a network of GPS receivers at high latitudes. We have used GPS data from five permanent receivers in Scandinavia, from 1–30 January 1994, with geographic latitudes ranging from 57.4°N to 78.9°N. The results show the capability of the method to monitor the evolution of TEC as a function of time and geographical location. We have detected night-time enhancements almost every night for some of the stations, and we have also been able to produce maps of the instantaneous TEC as a function of both latitude and longitude around the GPS network. We also present some of the current limitations in the use of GPS for estimating TEC at high latitudes such as the difficulties in solving for cycle-slips, and the necessity of reliable values for the receiver and satellite differential instrumental biases. 相似文献
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《Journal of Atmospheric and Solar》2007,69(7):803-816
Continuous monitoring of ionospheric conditions is essential to monitoring and forecasting space weather. The worldwide use of global navigation satellite systems like the Gobal Positioning System (GPS) makes it possible to continuously monitor the total electron content (TEC) of the ionosphere and plasmasphere up to a height of about 20,000 km. We have developed a system for deriving the TEC from GEONET data rapidly and we use the TEC distribution over Japan in the daily operations of the Space Weather Forecast Center at NICT (RWC Tokyo of ISES). Using instrumental biases from a few days before enables us to drastically shorten the processing time for deriving TEC. The latest TEC values (with a delay of about 1 h) are obtained every 3 h, and most of the values are within 2 TEC units of the actual TEC. We have found our system for deriving TEC rapidly to be useful for continuously monitoring the progress of ionospheric storms under any ionospheric conditions, even those under which the usual ionosonde observations are unable to obtain F-region profiles. 相似文献
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Adela Anghel Charles Carrano Attila Komjathy Adina Astilean Tiberiu Letia 《Journal of Atmospheric and Solar》2009,71(1):158-174
Data collected from a GPS receiver located at low latitudes in the American sector are used to investigate the performance of the WinTEC algorithm [Anghel et al., 2008a, Kalman filter-based algorithm for near realtime monitoring of the ionosphere using dual frequency GPS data. GPS Solutions, accepted for publication; for different ionospheric modeling techniques: the single-shell linear, quadratic, and cubic approaches, and the multi-shell linear approach. Our results indicate that the quadratic and cubic approaches perform much better than the single-shell and multi-shell linear approaches in terms of post-fit residuals. The performance of the algorithm for the cubic approach is then further tested by comparing the vertical TEC predicted by WinTEC and USTEC [Spencer et al., 2004. Ionospheric data assimilation methods for geodetic applications. In: Proceedings of IEEE PLANS, Monterey, CA, 26–29 April, pp. 510–517] at five North American stations. In addition, since the GPS-derived total electron content (TEC) contains contributions from both ionospheric and plasmaspheric sections of the GPS ray paths, in an effort to improve the accuracy of the TEC retrievals, a new data assimilation module that uses background information from an empirical plasmaspheric model [Gallagher et al., 1988. An empirical model of the Earth's plasmasphere. Advances in Space Research 8, (8)15–(8)24] has been incorporated into the WinTEC algorithm. The new Kalman filter-based algorithm estimates both the ionospheric and plasmaspheric electron contents, the combined satellite and receiver biases, and the estimation error covariance matrix, in a single-site or network solution. To evaluate the effect of the plasmaspheric component on the estimated biases and total TEC and to assess the performance of the newly developed algorithm, we compare the WinTEC results, with and without the plasmaspheric term included, at three GPS receivers located at different latitudes in the American sector, during a solar minimum period characterized by quiet and moderate geomagnetic conditions. We also investigate the consistency of our plasmaspheric results by taking advantage of the specific donut-shaped geometry of the plasmasphere and applying the technique at 12 stations distributed roughly over four geomagnetic latitudes and three longitude sectors. 相似文献
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电离层掩星观测中，当低轨卫星（LEO）轨道高度较低时，轨道以上的电离层电子总含量（TEC）对掩星反演的影响不能忽略.目前，一般采用指数函数等外推方法来处理该问题，对反演结果可能引起较大误差.为提高电离层掩星反演精度，本文研究利用LEO处于非掩星一侧GPS观测数据的改正TEC新反演方法.用三维射线追踪程序计算出电离层掩星观测模拟数据，分别应用改正TEC方法和外推方法进行反演，将反演结果与所用模式值进行比较.结果表明：对于轨道高度约800km的GPS/MET掩星模拟数据，外推方法和改正TEC方法反演结果都与模式值基本一致；对于轨道高度约400km的CHAMP掩星模拟数据，外推方法误差较大，改正TEC方法反演结果与模式值相符得较好.将改正TEC方法应用于GPS/MET实测数据的反演，取得了合理的结果.这些说明，改正TEC算法是一种有效的电离层掩星反演方法，尤其是对于轨道较低的LEO的电离层掩星观测反演特别有用. 相似文献
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M.C. deLacy F. Sansò A.J. Gil G. Rodríguez-Caderot 《Studia Geophysica et Geodaetica》2005,49(1):63-84
To estimate ionospheric delays from the Global Positioning System (GPS) measurements, satellite and receiver equipment biases have to be modeled. This paper presents a procedure based on the least squares (LS) approach, which implicitly takes into account these equipment biases in the estimation of the ionospheric effect. The second part of this work deals with the interpolation of the ionospheric correction from a permanent GPS network to a single frequency GPS user. The results obtained show that for 10-cm position accuracy the ionospheric delay can be successfully interpolated when the GPS user is within 40 km of the GPS permanent network. 相似文献