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Quality monitoring of real-time GNSS precise positioning service system

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geo-Spatial Information Science 2023年第1期26卷 1-15页

作者： Run Ji Xinyuan Jiang Xinghan Chen Huizhong Zhu maorong ge Frank Neitzel Institute of geodesy and geoinformation Science Technische Universität BerlinBerlinGermany german Research Center for geosciences(GFZ) PotsdamGermany School of geomatics Liaoning Technical University(LNTU)Fuxin 123000China

The Real-Time Global Navigation Satellite System(GNSS)Precise Positioning Service(RTPPS)is recognized as the most promising system by providing precise satellite orbit and clock correc-tions for users to achieve centimeter-level positioning with a stand-alone receiver in *** the products are available with high accuracy almost all the time,they may occasionally suffer from unexpected significant biases,which consequently degrades the positioning ***,quality monitoring at the system-level has become more and more crucial for providing a reliable GNSS *** this paper,we propose a method for the monitoring of realtime satellite orbit and clock products using a monitoring station network based on the Quality Control(QC)*** satellites with possible biases are first detected based on the outliers identified by Precise Point Positioning(PPP)in the monitoring station ***,the corresponding orbit and clock parameters with temporal constraints are introduced and esti-mated through the sequential Least Square(LS)estimator and the corresponding Instantaneous User Range Errors(IUREs)can be determined.A quality indicator is calculated based on the IUREs in the monitoring network and compared with a pre-defined *** quality monitoring method is experimentally evaluated by monitoring the real-time orbit and clock products generated by geoForschungsZentrum(GFZ),*** results confirm that the problematic satellites can be detected accurately and effectively with missed detection rate 4×10^(-6) and false alarm rate 1:2×10^(-5).Considering the quality alarms,the PPP results in terms of RMS of positioning differences with respect to the International GNSS Service(IGS)weekly solution in the north,east and up directions can be improved by 12%,10%and 27%,respectively.

关键词： Global Navigation Satellite System(GNSS) real-time precise positioning quality monitoring precise point positioning satellite product bias

LEO Enhanced Global Navigation Satellite System(LeGNSS):progress,opportunities,and challenges

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geo-Spatial Information Science 2022年第1期25卷 1-13页

作者： Haibo ge Bofeng Li Song Jia Liangwei Nie Tianhao Wu Zhe Yang Jingzhe Shang Yanning Zheng maorong ge College of Surveying and geo-Informatics Tongji UniversityShanghaiChina Department of geodesy GeoForschungsZentrum(GFZ)TelegrafenbergPotsdamGermany

With the completion of Chinese BeiDou Navigation Satellite System(BDS),the world has begun to enjoy the Positioning,Navigation,and Timing(PNT)services of four Global Navigation Satellite Systems(GNSS).In order to improve the GNSS performance and expand its applications,Low Earth Orbit(LEO)Enhanced Global Navigation Satellite System(LeGNSS)is being vigorously *** with high-,medium-,and low-earth orbit satellites,it can improve GNSS performance in terms of orbit determination,Precise Point Positioning(PPP)convergence time,*** paper comprehensively reviews the current status of LeGNSS,focusing on analyzing its advantages and challenges for precise orbit and clock determination,PPP convergence,earth rotation parameter estimation,and global ionosphere *** to the fast geometric change brought by LEO satellites,LeGNSS is expected to fundamentally solve the problem of the long convergence time of PPP without any *** convergence time can be shortened within 1 minute if appropriate LEO constellations are ***,there are still some issues to overcome,such as the optimization of LEO constellation as well as the real time LEO precise orbit and clock determination.

关键词： LEO Enhanced Global Navigation Satellite System(LeGNSS) orbit determination Precise Point Positioning(PPP) convergence time global ionosphere modeling

A square root information filter for multi-GNSS real-time precise clock estimation

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Satellite Navigation 2021年第1期2卷 400-413页

作者： Xiang Zuo Xinyuan Jiang Pan Li Jungang Wang maorong ge Harald Schuh Department of geodesy GeoForschungsZentrum(GFZ)Telegrafenberg14473 PotsdamGermany Institut Für geodäsie Und geoinformationstechnik Technische Universität BerlinKaiserin-Augusta-Allee 104-10610553 BerlinGermany.

Real-time satellite orbit and clock estimations are the prerequisite for Global Navigation Satellite System(GNSS)real-time precise positioning *** meet the high-rate update requirement of satellite clock corrections,the computational efficiency is a key factor and a challenge due to the rapid development of multi-GNSS *** Square Root Information Filter(SRIF)is widely used in real-time GNSS data processing thanks to its high numerical stability and computational *** real-time clock estimation,the outlier detection and elimination are critical to guarantee the precision and stability of the product but could be *** this study,we developed a new quality control procedure including the three standard steps:i.e.,detection,identification,and adaption,for real-time data processing of huge GNSS *** is made to improve the computational efficiency by optimizing the algorithm to provide only the essential information required in the processing,so that it can be applied in real-time and high-rate estimation of satellite *** processing procedure is implemented in the PANDA(Positioning and Navigation Data Analyst)software package and evaluated in the operational generation of real-time GNSS orbit and clock *** demonstrated that the new algorithm can efficiently eliminate outliers,and a clock precision of 0.06 ns,0.24 ns,0.06 ns,and 0.11 ns can be achieved for the GPS,GLONASS,Galileo,and BDS-2 IGSO/MEO satellites,*** computation time per epoch is about 2 to 3 s depending on the number of existing ***,the algorithm can satisfy the IGS real-time clock estimation in terms of both the computational efficiency and product quality.

关键词： SRIF Precise clock estimation Quality control Real-time GNSS

Precise Relative Orbit Determination of Twin GRACE Satellites

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geo-Spatial Information Science 2010年第3期13卷 221-225页

作者： ZHAO Qile HU Zhigang GUO Jing LI Min ge maorong GNSS Research Center Wuhan University 129 Luoyu Road Wuhan 430079 China Department of geodesy and Remote Sensing GeoForschungsZentrum (GFZ) Potsdam Telegrafenberg A17 D14473 Potsdam Germany

When formation flying spacecrafts are used as platform to gain earth oriented observation, precise baselines between these spacecrafts are always essential. Gravity recovery and climate experiment （GRACE） mission is aimed at mapping the global gravity field and its variation. Accurate baseline of GRACE satellites is necessary for the gravity field modeling. The determination of kinematic and reduced dynamic relative orbits of twin satellites has been studied in this paper, and an accuracy of 2 mm for dynamic relative orbits and 5 mm for kinematic ones can be obtained, whereby most of the double difference onboard GPS ambiguities are resolved.

关键词： GRACE gravity field modeling formation flying spacecraft relative orbit determination

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PPP-RTK considering the ionosphere uncertainty with cross-validation

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Satellite Navigation 2022年第1期3卷 34-46,I0002页

作者： Pan Li Bobin Cui Jiahuan Hu Xuexi Liu Xiaohong Zhang maorong ge Harald Schuh College of geology Engineering and geomatics Chang’an UniversityXi’an 710054China Department of geodesy GeoForschungsZentrum(GFZ)14473 TelegrafenbergPotsdamGermany Technische Universität Berlin Straße des 17.Juni 13510623 BerlinGermany l4 Department of Earth and Space Science and Engineering York UniversityTorontoON M3J 1P3Canada School of geodesy and geomatics Wuhan UniversityWuhan 430079China

With the high-precision products of satellite orbit and clock,uncalibrated phase delay,and the atmosphere delay corrections,Precise Point Positioning(PPP)based on a Real-Time Kinematic(RTK)network is possible to rapidly achieve centimeter-level positioning *** the ionosphere-weighted PPP–RTK model,not only the a priori value of ionosphere but also its precision afect the convergence and accuracy of *** study proposes a method to determine the precision of the interpolated slant ionospheric delay by *** new method takes the high temporal and spatial variation into consideration.A distance-dependent function is built to represent the stochastic model of the slant ionospheric delay derived from each reference station,and an error model is built for each reference station on a fve-minute piecewise *** user can interpolate ionospheric delay correction and the corresponding precision with an error function related to the distance and time of each reference *** the European Reference Frame(EUREF)Permanent GNSS(Global Navigation Satellite Systems)network(EPN),and SONEL(Système d’Observation du Niveau des Eaux Littorales)GNSS stations covering most of Europe,the efectiveness of our wide-area ionosphere constraint method for PPP-RTK is validated,compared with the method with a fxed ionosphere precision *** is shown that although the Root Mean Square(RMS)of the interpolated ionosphere error is within 5 cm in most of the areas,it exceeds 10 cm for some areas with sparse reference stations during some periods of *** convergence time of the 90th percentile is 4.0 and 20.5 min for horizontal and vertical directions using Global Positioning System(GPS)kinematic solution,respectively,with the proposed *** convergence is faster than those with the fxed ionosphere precision values of 1,8,and 30 *** improvement with respect to the latter three solutions ranges from 10 to 60%.After integrating the Galileo navi

关键词： PPP-RTK Ionosphere precision Cross-validation Rapid ambiguity resolution

THE STOCHASTIC ESTIMATION OF SATELLITE CLOCK CORRECTION INFORMATION IN WADGPS

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geo-Spatial Information Science 2000年第1期3卷 66-69页

作者： Hseyin Bki Iz ge maorong Esmond Mok

Using autocorrelation information of the pseudorange errors generated by se- lective availability (SA) frequency dithering, we have constructed a simple first order stochas- tic model for SA effects. This model has been used in a Kalman filter to account for the stochastic behavior of SA dithering in estimating satellite clock information in wide area dif- ferential GPS. We have obtained fifteen percent improvement in the user positioning using the correlation information on the satellite clock information in a Kalman filter, when comparing the results obtained using a regular least square estimation.

关键词： stochastic model wide area differential GPS(WADGPS) selective availability

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Multi‐GNSS Processing Combining GPS, GLONASS, BDS and GALILEO Observations

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Multi‐GNSS Processing Combining GPS, GLONASS, BDS and GALIL...

Analysis of the Effect of the 06-09-2017 Solar Flare on GNSS Signal and Positioning Performance

第五届中国卫星导航学术年会

作者： Cui Hongzheng Tang geshi Hu Songjie Song Baiyan Liu Huicui Sun Jing Zhang Peng Li Cuilan ge maorong Han Chao Flight Dynamics Laboratory Beijing Aerospace Control Center School of Astronautics Beijing University of Aeronautics and Astronautics german Research Center for geosciences

ISBN: (纸本)9783642547393

Coexistence and development of four kinds of Global Satellite Navigation System, GPS, GLONASS, BDS, and GALILEO have initially established. In order to benefit from multi-GNSS applications, including increase in usable SVs, signals and frequencies, increase in availability and coverage, more robust and reliable services, and so on, firstly we need to obtain the precise multi-GNSS orbit and clock in a unified space and time frame. Based on the knowledge of the EPOS and EPOS-RT （Earth Parameter and Orbit determination System in Real-Time） software package, Beijing Aerospace Control Center （BACC） has been working on his own software package for multi-GNSS data processing. This paper firstly introduces the multi-GNSS processing strategies in detail, and adopts additional inter system biases parameter （ISB） except the normal IGS and GFZ observation model and dynamic model. On the basis of above strategies and the observation data from a network of multi-GNSS capable receivers from the IGS Multi-GNSS EXperiment （MgeX） and a regional BDS station network operated by China, the experiments and simulation are carried out. The results are validated against products from other institutes and by overlap comparison. The impact on orbit and clock precision by combined processing against single system processing is investigated and the improvement on precise point positioning （PPP） is also evaluated.

关键词： Multi-GNSS Combined Data Processing Inter System Biases (ISB) Orbit overlap Precise Point Positioning (PPP)

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Analysis of the Effect of the 06-09-2017 Solar Flare on GNSS...

GBM快速轨道产品及非差模糊度固定对其精度的改进

第九届中国卫星导航学术年会

作者： Wei Zhou Shegnfeng Gu maorong ge Jungang Wang LEETC geo Forschungs Zentrum (GFZ) Potsdam GNSS Research Center Wuhan University

This paper investigates the effect of 06-09-2017 X9.3 solar flare on Global Navigation Satellite System(GNSS) signal and positioning performance. To conduct the study we select 60 IGS stations and collect the observations and ephemeris from August 30 to September 13, 2017. The Solar activity Indexes of Ap, Kp, Dst are evaluated and the global ROTI maps are constructed to indicate and define the magnitude of the storm. As for the GNSS signal, signal-in-space-ranging-errors(SISRE) is used to assess the solar flare’s effect on the accuracy of broadcast ephemeris, and the cycle slip occurrence is used to assess it’s impact on observation quality, especially phase observation. Furthermore, the kinematic GNSS PPP solution is used to evaluate the GNSS positioning performance during the storm. After processing, root mean square errors(RMS) of north, east and up component were calculated for each station on each day. The results indicate that at eight of all the selected IGS stations three-dimensional(3 D) accuracy of PPP has degraded significantly and the GNSS are unreliable during the storm.

关键词： GNSS solar flare ROTI SISRE PPP performance

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测绘学报 2022年第4期51卷 544-555页

作者：邓志国王君刚葛茂荣德国地学中心德国波茨坦14473 中国科学院上海天文台上海200030 柏林工业大学德国柏林10553

GNSS是实时定位导航最重要的方法,精密卫星轨道钟差产品是GNSS高精度服务的前提。国际GNSS服务中心(IGS)及其分析中心长期致力于GNSS数据处理的研究及高精度轨道和钟差产品的提供。GFZ作为分析中心之一,提供GBM多系统快速产品。本文基于... 详细信息

GNSS是实时定位导航最重要的方法,精密卫星轨道钟差产品是GNSS高精度服务的前提。国际GNSS服务中心(IGS)及其分析中心长期致力于GNSS数据处理的研究及高精度轨道和钟差产品的提供。GFZ作为分析中心之一,提供GBM多系统快速产品。本文基于2015—2021年GBM提供的精密轨道产品,阐述了数据处理策略,分析了轨道的精度,介绍了非差模糊度固定的原理和对精密定轨的影响。结果表明:GBM快速产品中的GPS轨道精度与IGS后处理精密轨道相比的精度约为11~13 mm,轨道6 h预报精度约为6 cm;GLONASS预报精度约为12 cm,Galileo在该时期的精度均值为10 cm,但是在2016年底以后精度提升到5 cm左右;北斗系统的中轨卫星(medium earth orbit,MEO)在2020年以后预报精度约为10 cm;北斗的静止轨道卫星(geostationary earth orbit,geO)卫星和QZSS卫星的预报精度在米级;卫星激光测距检核表明,Galileo、GLONASS、BDS-3 MEO卫星轨道精度分别为23、41、47 mm;此外,采用150 d观测值的试验结果表明,采用非差模糊度固定能显著改善MEO卫星轨道精度,对GPS、GLONASS、Galileo、BDS-2和BDS-3的MEO卫星的6 h时预报精度改善率分别为9%~15%、15%~18%、11%~13%、6%~17%和14%~25%。

关键词： GNSS 精密定轨模糊度固定

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