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Signal-in-space accuracy for BeiDou navigation satellite system:Challenges and solutions

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Science china(Physics,Mechanics & Astronomy) 2017年第1期60卷 84-86页

作者： shanshi zhou {2. Wu xiaogong hu YueLing Cao Yang Yu shanghai astronomical {2. Chinese Academy of Sciences Shanghai 200030 China

Service accuracy of global navigation satellite system （GNSS） is determined by satellite constellation, sig- nal-in-space （SIS） accuracy and signal transmission errors. The State Council Information Office of the People＇s Repub- lic of china issued china＇s BeiDou Navigation Satellite Sys- tem （BDS） White Paper （***/***） on Jun. 16th 2.16, which notes that, BDS takes a three-step development strategy, from domestic service, through Asia-Pacific regional service, to global service, and features mixed constellation of Geostationary Earth Orbit （GEO）, Inclined Geostationary Earth Orbit （IGSO） and Medium Earth Orbit （MEO） satellites.

关键词： navigation constellation Medium notes GNSS issued Republic

Orbit determination and prediction for Beidou GEO satellites at the time of the spring/autumn equinox

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Science china(Physics,Mechanics & Astronomy) 2015年第8期58卷 86-94页

作者： LI XiaoJie zhou Jianhua hu xiaogong LIU Li GUO Rui zhou shanshi Beijing Satellite Navigation Center shanghai Key Laboratory of Space Navigation and Position Techniques shanghai astronomical {2. Chinese Academy of Sciences

Geostationary(GEO) satellites form an indispensable component of the constellation of Beidou navigation system(BDS). The ephemerides, or predicted orbits of these GEO satellites(GEOs), are broadcast to positioning, navigation, and timing users. User equivalent ranging error(UERE) based on broadcast message is better than 1.5 m(root formal errors: RMS) for GEO satellites. However, monitoring of UERE indicates that the orbital prediction precision is significantly degraded when the Sun is close to the Earth's equatorial plane(or near spring or autumn Equinox). Error source analysis shows that the complicated solar radiation pressure on satellite buses and the simple box-wing model maybe the major contributor to the deterioration of orbital precision. With the aid of BDS' two-way frequency and time transfer between the GEOs and Beidou time(BDT, that is maintained at the master control station), we propose a new orbit determination strategy, namely three-step approach of the multi-satellite precise orbit determination(MPOD). Pseudo-range(carrier phase) data are transformed to geometric range(biased geometric range) data without clock offsets; and reasonable empirical acceleration parameters are estimated along with orbital elements to account for the error in solar radiation pressure modeling. Experiments with Beidou data show that using the proposed approach, the GEOs' UERE when near the autumn Equinox of 2.12.can be improved to 1.3 m from 2.5 m(RMS), and the probability of user equivalent range error(UERE)2.0 m can be improved from 50% to above 85%.

关键词： Beidou system (BDS) Beidou time (BDT) geostationary (GEO) satellite spring equinox/autumn equinox solar radia-tion pressure time synchronization user equivalent ranging error

基于国产ARM架构CPU的导航卫星精密定轨解算效率优化方法

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大地测量与地球动力学 2024年第4期44卷 366-371页

作者：廖敏唐成盼周善石陈建兵胡小工冯学斌陈桂根李凯中国科学院上海天文台上海市200030 中国科学院大学北京市100049 探索数据科技(深圳)有限公司深圳市518055

以国产飞腾CPU为例,讨论在国产ARM架构CPU基础上的导航卫星精密定轨解算效率优化方法。基于导航卫星精密定轨解算流程中钟差约化和法方程求逆耗时较多,分别利用多线程和OpenBlas对上述2.过程进行优化。结果表明,优化后解算效率大幅提... 详细信息

以国产飞腾CPU为例,讨论在国产ARM架构CPU基础上的导航卫星精密定轨解算效率优化方法。基于导航卫星精密定轨解算流程中钟差约化和法方程求逆耗时较多,分别利用多线程和OpenBlas对上述2.过程进行优化。结果表明,优化后解算效率大幅提升。钟差约化方面,采用100个测站32.导航卫星进行解算时,原始单历元平均耗时1.105 s,优化后为0.188 s;法方程求逆方面,原始求逆平均耗时2.2.4 s,优化后仅需78 s。

关键词：精密定轨 ARM架构CPU 多线程 OpenBlas

Inter-satellite link augmented BeiDou-3 orbit determination for precise point positioning

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chinese Journal of Aeronautics 2022年第4期35卷 332-343页

作者： Liqian ZHAO xiaogong hu Chengpan TANG {2. zhou Yueling CAO Qianxin WANG Ranran SU Space Star Technology Co. Ltd.Beijing 100095China shanghai astronomical {2. Chinese Academy of SciencesShanghai 200030China School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou 221116China Beijing Satellite Navigation Center Beijing 100094China

Precise Point Positioning(PPP) requires precise products, including high-accuracy satellite orbit and clock parameters. It is impossible to obtain an orbit solution that is sufficiently accurate for PPP services with a regional tracking network;therefore, satellite orbits are usually estimated by a global tracking network with a large number of ground stations. However, it is expensive to build globally distributed stations. Fortunately, BeiDou-3 satellites carry an InterSatellite Link(ISL) payload, which can track the whole arc of the BeiDou-3 satellites and enhance the orbit determination accuracy with regional ground stations. In this contribution, a novel orbit determination strategy for BeiDou-3 PPP is proposed, in which the BeiDou-3 satellite orbits are enhanced by the ISL. First, the generation of precise satellite products is demonstrated in *** addition, the products are assessed by Satellite Laser Ranging(SLR) residuals and overlap comparisons. Moreover, the products are used for receivers in china's Mainland to carry out the static and kinematic modes to research the PPP performance of Bei Dou-3’s 3IGSO/2.MEO *** SLR validations of the satellite orbits demonstrate an accuracy better than 0.1 m in the radial component, and the orbit overlap comparisons show accuracies of 0.016 m in the radial component,0.088 m in the along-track component and 0.087 m in the cross-track component. The Standard Deviation(STD) in the differences in overlapping arcs for the estimated satellite clocks is approximately 0.10 ns. The static PPP results demonstrate that the error in both the horizontal and vertical components is smaller than 10 cm after 30 minutes of convergence. After 2. hours of convergence,the errors are 0.70 cm, 0.63 cm and 1.99 cm for the north, east and up components, *** kinematic PPP experiment illustrates that the Root Mean Square(RMS) position errors in the north, east and up components are approximately 3.2. cm, 5.2. cm a

关键词： BeiDou-3 Clock offsets Convergence Inter-satellite link Precise Point Positioning Regional ground stations Satellite orbits

Positioning accuracy assessment for the 4GEO/5IGSO/2.EO constellation of COMPASS

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Science china(Physics,Mechanics & Astronomy) 2012年第12期55卷 2290-2299页

作者： zhou shanshi CAO YueLing zhou Jianhua hu xiaogong TANG ChengPan LIU Li GUO Rui HE Feng CHEN JunPing WU bin shanghai astronomical {2. Chinese Academy of SciencesShanghai 200030China Beijing Global lnformation Application and Development Center Beijing 100094China

Determined to become a new member of the well-established GNSS family,COMPASS(or BeiDou-2. is developing its capabilities to provide high accuracy positioning *** positioning modes are investigated in this study to assess the positioning accuracy of COMPASS' 4GEO/5IGSO/2.EO *** Point Positioning(PPP) for geodetic users and real-time positioning for common navigation users are *** evaluate PPP accuracy,coordinate time series repeatability and discrepancies with GPS' precise positioning are *** show that COMPASS PPP repeatability for the east,north and up components of a receiver within china's Mainland is better than 2.cm,2.cm and 5 cm,*** systematic offsets of several centimeters exist between COMPASS precise positioning and GPS precise positioning,indicating errors remaining in the treatments of COMPASS measurement and dynamic models and reference frame differences existing between two *** common positioning users,COMPASS provides both open and authorized services with rapid differential corrections and integrity information available to authorized *** assessment shows that in open service positioning accuracy of dual-frequency and single-frequency users is about 5 m and 6 m(RMS),respectively,which may be improved to about 3 m and 4 m(RMS) with the addition of differential *** accurate Signal In Space User Ranging Error(SIS URE) and Geometric Dilution of Precision(GDOP) contribute to the relatively inferior accuracy of COMPASS as compared to *** the deployment of the remaining 1 GEO and 2.MEO is not able to significantly improve GDOP,the performance gap could only be overcome either by the use of differential corrections or improvement of the SIS URE,or both.

关键词： PPP real-time positioning authorized services orbit determination

Satellite-station time synchronization information based real-time orbit error monitoring and correction of navigation satellite in Beidou System

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Science china(Physics,Mechanics & Astronomy) 2014年第7期57卷 1395-1403页

作者： HE Feng zhou shanshi {2. xiaogong zhou Jian{2.a LIU Li GUO Rui LI XiaoJie WU Shan shanghai astronomical {2. Chinese Academy of Sciences Graduate University of chinese academy of sciences Beijing Satellite Navigation Center

Satellite-station two-way time comparison is a typical design in Beidou System(BDS)which is significantly different from other satellite navigation *** a type of two-way time comparison method,BDS time synchronization is hardly influenced by satellite orbit error,atmosphere delay,tracking station coordinate error and measurement model ***,single-way time comparison can be realized through the method of Multi-satellite Precision Orbit Determination(MPOD)with pseudo-range and carrier phase of monitor *** is proved in the constellation of 3GEO/2.GSO that the radial orbit error can be reflected in the difference between two-way time comparison and single-way time comparison,and that may lead to a substitute for orbit evaluation by *** this article,the relation between orbit error and difference of two-way and single-way time comparison is illustrated based on the whole constellation of *** the all-weather and real-time operation mode of two-way time comparison,the orbit error could be quantifiably monitored in a real-time mode through comparing two-way and single-way time *** addition,the orbit error can be predicted and corrected in a short time based on its periodic *** is described in the experiments of GEO and IGSO that the prediction accuracy of space signal can be obviously improved when the prediction orbit error is sent to the users through navigation message,and then the UERE including terminal error can be reduced from 0.1 m to 0.4 m while the average accuracy can be improved more than 2.%.Though it is still hard to make accuracy improvement for Precision Orbit Determination(POD)and orbit prediction because of the confined tracking net and the difficulties in dynamic model optimization,in this paper,a practical method for orbit accuracy improvement is proposed based on two-way time comparison which can result in the reflection of orbit error.

关键词： satellite navigation orbital mechanics time synchronization ephemeris fitting

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弹载GNSS虚拟参考站差分定位技术研究

兵器装备工程学报 2024年第8期45卷 67-73页

作者：吴庆丰宋叶志闫正洲夏凤雨李静罗鹏周善石胡小工赵炽西华师范大学四川南充637002 中国科学院上海天文台上海200030 中国科学院大学北京100049

针对高动态目标定位的长基线实时解算需要,本研究采网络多基站融合技术,结合基准站与线性内插模型算法,生成虚拟参考站伪距观测值,并将虚拟参考站作为基准站与目标进行伪距差分解算,从而解算高动态目标的位置轨迹。通过静态目标与高动... 详细信息

针对高动态目标定位的长基线实时解算需要,本研究采网络多基站融合技术,结合基准站与线性内插模型算法,生成虚拟参考站伪距观测值,并将虚拟参考站作为基准站与目标进行伪距差分解算,从而解算高动态目标的位置轨迹。通过静态目标与高动态目标的实测数据验证,在有3个基准站的情况下,静态数据的定位精度达到0.399 m;而高动态目标在目标与基准站共视卫星个数不少于6颗的情况下,定位中误差不超过2.750 m;而与光学雷达、多测速雷达等其他外测设备的实测综合轨迹相比,两者之间位置差异的均方根值为6.390 m,基本满足高动态目标的定位需要。

关键词：网络伪距差分虚拟参考站技术弹道测量扩展卡尔曼滤波线性内插模型

The wide-area difference system for the regional satellite navigation system of COMPASS

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Science china(Physics,Mechanics & Astronomy) 2012年第7期55卷 1307-1315页

作者： CAO YueLing hu xiaogong WU {2. zhou shanshi LIU Li SU RanRan CHANG ZhiQiao HE Feng zhou Jianhua shanghai astronomical {2. Chinese Academy of Sciences Shanghai 200030 China Graduate University of chinese academy of Seiences Beijing 100049 China Beijing Global Information Application and Development Center Beijing 100094 China

The regional satellite navigation system of COMPASS (Phase I) provides both open services and authorized services. Authorized services offer differential corrections and integrity information to users to support higher positioning, navigation and timing precision. Experimenting with real data, positioning accuracy is estimated with a 3GEO/4IGSO COMPASS constellation. The results show that with dual-frequency and single-frequency pseudo-range measurements, the positioning errors are respectively 8 and 10 m (RMS) for open service users, while for authorized users, the errors are 4 and 5 m (RMS), respectively. The COMPASS constellation geometry may cause large error to occur in the height component by 7-9 m for dualor single-frequency users, which can be effectively reduced with the differential corrections supplied by the authorized services. Multipath errors are identified and corrected for COMPASS, resulting in 2.% positioning accuracy improvement for dual-frequency users and 10% improvement for single-frequency users.

关键词： COMPASS equivalent satellite clock error ionospheric grid multipath error positioning error

Applications of two-way satellite time and frequency transfer in the BeiDou navigation satellite system

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Science china(Physics,Mechanics & Astronomy) 2016年第10期59卷 72-80页

作者： shanshi zhou {2. hu Li Liu Rui Guo LingFeng Zhu ZhiQiao Chang ChengPan Tang XiuQiang Gong Ran Li Yang Yu shanghai astronomical {2. Chinese Academy of SciencesShanghai 200030China Beijing Satellite Navigation Center Beijing 100094China

A two-way satellite time and frequency transfer(TWSTFT) device equipped in the BeiDou navigation satellite system(BDS)can calculate clock error between satellite and ground master clock. TWSTFT is a real-time method with high accuracy because most system errors such as orbital error, station position error, and tropospheric and ionospheric delay error can be eliminated by calculating the two-way pseudorange difference. Another method, the multi-satellite precision orbit determination(MPOD)method, can be applied to estimate satellite clock errors. By comparison with MPOD clock estimations, this paper discusses the applications of the BDS TWSTFT clock observations in satellite clock measurement, satellite clock prediction, navigation system time monitor, and satellite clock performance assessment in orbit. The results show that with TWSTFT clock observations, the accuracy of satellite clock prediction is higher than MPOD. Five continuous weeks of comparisons with three international GNSS Service(IGS) analysis centers(ACs) show that the reference time difference between BeiDou time(BDT) and golbal positoning system(GPS) time(GPST) realized IGS ACs is in the tens of nanoseconds. Applying the TWSTFT clock error observations may obtain more accurate satellite clock performance evaluation in the 104 s interval because the accuracy of the MPOD clock estimation is not sufficiently high. By comparing the BDS and GPS satellite clock performance, we found that the BDS clock stability at the 103 s interval is approximately 10.12. which is similar to the GPS IIR.

关键词： BDS TWSTFT satellite clock prediction accuracy system reference time Allan variance