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A virtual reference satellite differential method for relative correction of satellite ephemeris errors

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Science china(Physics,Mechanics & Astronomy) 2010年第12期53卷 2300-2306页

作者： CAI ChengLin 1,3 , LI xiaoHui 2,3 & WU HaiTao 2,3 1 Gulin University of Electronic Technology, 541004, china 2 national time service center, chinese academy of sciences, Lintong 710600, china 3 key laboratory of Precision navigation and timing Technology, national time service center, chinese academy of sciences, Lintong 710600, china 1. Gulin University of Electronic Technology Gulin 541004 China3. Key Laboratory of Precision Navigation and Timing Technology National Time Service Center Chinese Academy of Sciences Lintong 710600 China2. National Time Service Center Chinese Academy of Sciences Lintong 710600 China

In order to solve the problems that the novel wide area differential method on the satellite clock and ephemeris relative correction (CERC) in the non-geostationary orbit satellite constellation, a virtual reference satellite (VRS) differential principle using relative correction of satellite ephemeris errors is proposed. It is referred to be as the VRS differential principle, and the elaboration is focused on the construction of pseudo-range errors of VRS. Through qualitative analysis, it can be found that the impact of the satellite’s clock and ephemeris errors on positioning can basically be removed and the users’ positioning errors are near zero. Through simulation analysis of the differential performance, it is verified that the differential method is universal in all kinds of satellite navigation systems with geostationary orbit (GEO) constellation, Medium orbit (MEO) constellation or hybrid orbit constellation, and it has insensitivity to abnormal aspects of a satellite ephemeris and clock. Moreover, the real time positioning accuracy of differential users can be maintained within several decimeters after the pseudo-range measurement noise is effectively weakened or eliminated.

关键词： wide area differential method virtual reference satellite (VRS) satellite ephemeris errors satellite clock errors constellation

A study on volunteer augmentation navigation technology

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Science china(Physics,Mechanics & Astronomy) 2011年第6期54卷 1029-1034页

作者： WU HaiTao 1,2,LU xiaoChun 1,2,ZOU DeCai 1,2 & HAN Tao 1,2 1 national time service center,chinese academy of sciences,xi’an 710600,china 2.key laboratory of Precision navigation and timing Technology,chinese academy of sciences,xi’an 710600,china 1. national time service center Chinese Academy of Sciences Xi’an 710600 China2. Key Laboratory of Precision Navigation and Timing Technology Chinese Academy of Sciences Xi’an 710600 China

navigation augmentation technology is one of the most common methods to increase the continuity,reliability and integrity of the global satellite navigation *** concept of volunteer augmentation navigation (VNA) is proposed and the elements and topological structure of VNA are also analyzed in this *** study focuses on the neural network model that volunteers and ordinary users use modern communication information network to exchange self-organizing *** neural cell model of Volunteer Augmentation navigation using shared information is *** interactive general relative positioning is *** basic theories and methods of volunteer augmentation navigation are formed on the basis of the above-mentioned *** study of realization mechanism of volunteer augmentation technology helps to form a relatively integral architecture of volunteer augmentation navigation.A user self-service satellite navigation augmentation which combines information exchange and navigation services may strengthen the continuity,reliability and integrity of the navigation *** volunteer augmentation navigation theory proposed in this paper improves the traditional satellite navigation application model and expands the connotation and denotation of satellite navigation augmentation methods.

关键词： volunteer augmentation navigation self-organizing information exchange interactive general relative positioning

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用于GNSS基带信号分析的相干累加算法

数据采集与处理 2009年第B10期24卷 124-127页

作者：贺成艳卢晓春中国科学院国家授时中心西安710600 中国科学院精密导航定位与定时重点实验室西安710600 中国科学院研究生院北京100190

在对一般累加平均算法的原理、应用条件和误差来源等进行分析的基础上,提出了一种可以适用于更高数据速率(如500 bps)的相干累加算法,并且不需要进行导航信息的剥离。通过实验分析表明,在经过一定周期累加以后,就可以在时域观测到清晰... 详细信息

在对一般累加平均算法的原理、应用条件和误差来源等进行分析的基础上,提出了一种可以适用于更高数据速率(如500 bps)的相干累加算法,并且不需要进行导航信息的剥离。通过实验分析表明,在经过一定周期累加以后,就可以在时域观测到清晰的扩频码波形,也证明了新的累加平均算法确实可以达到提高信噪比的目的,而且比一般方法要好。

关键词：相干累加基带信号 GNSS 信噪比

Research on AutoNav-Guiding Technology for Airplane Taxiing

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Research on AutoNav-Guiding Technology for Airplane Taxiing

第三届中国卫星导航学术年会

作者： Wu Hai-tao1 2 Zou De-cai1 2 Han Tao1 2 Lu xiao-chun1 2 1.national time service center chinese academy of sciences xi’an 710600 china 2.key laboratory of Precision navigation and timing Technology chinese academy of sciences xi’an 710600 china

Aircraft taxiing on the ground can reach or leave from parking bay with the help of"FOLLOW ME"airport guide car,a process that requires a lot of manpower,material and financial *** the extensive use of Satellite-based navigation system and the rapid development of modern communication technology and automatic control technology,this paper presents and studies aircraft automatic guidance technology to replace the airport guide car during airplane *** basic idea is that,based on the landing PVT information provided by GNSS navigation equipment onboard the aircraft,control tower planes aircraft taxiing routes after landing automatically according to airport GIS data and the actual airport flight schedule,and sends to the aircraft crew through wireless communication *** crew will match the real-time aircraft GNSS positioning information to the taxiing route provided by control tower using finite element theory coordinates matching *** matching results will be shown on the cockpit Multi-Function Display（MFD）or on the Head-up Display of windshield glass with the flashing arrows to guide the pilot taxiing under the established ***-guiding technology occupies a certain advantage in the implementation complexity,cost,size and energy consumption compared to aircraft taxiing with the help of airport guide car,and auto-guiding technology can also be used for the machine automatic guidance in the other places.

关键词： AutoNav-Guiding taxiing route finite element coordinates matching

Application of GNSS in School Bus Safety Monitoring

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Application of GNSS in School Bus Safety Monitoring

第三届中国卫星导航学术年会

作者： HAN Tao1 2 LU xiaochun1 2 ZOU Decai1 2 1.national time service center xi’an 710600 P.R.china 2.key laboratory of Precision navigation and timing Technology chinese academy of sciences xi’an 710600 P.R.china

With the "Regulations of the School Bus Safety（draft）" issued by the State Council at the end of 2011,the management of school bus safety transportation has become a hot *** article puts forward a method of using Global navigation Satellite System（GNSS）to monitor the school bus *** school bus transport and management system,which is real-time,accurate and efficient,will be built up by integrate satellite positioning technology,information technology,data transmission technology,electronic sensor technology,information processing technology and emergency services ***,the difference between the school bus monitoring and general vehicle monitoring is pointed ***,we find out the main reason is overload of passengers which cause the phenomenon of frequent school bus accident in ***,a School Bus Overloading Monitoring System（School-Bus-OMS）is designed to prevent the phenomenon of overload of *** that,the school bus safety monitoring system which based on GNSS and School-Bus-OMS is ***,a detailed description on the structure,function and rescuing measures of this system are given,and the corresponding mathematical models are established.

关键词： School Bus Safety GNSS Pressure Monitoring Mathematical Modeling

Study on the Selection and Estimation of the Technique Index System of time ＆ Frequency of Satellite navigation Systems

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Study on the Selection and Estimation of the Technique Index...

第三届中国卫星导航学术年会

作者： Ren xiaoqian1,2, Hu Yu1,2, Wu Haitao1,2, Guo Wei1,2, Qin Weijin1,2 1. national time service center, chinese academy of sciences, xi’an 710600, china 2. key laboratory of Precision navigation and timing Technology, chinese academy of sciences, xi’an 710600, china

The satellite navigation system is based on the measurements of time ＆ frequency to achieve distance, position and velocity measurements. The positioning is one of the functions of the satellite navigation system. The paper is based on the analysis of working principle of the satellite navigation system and the characteristic of strong relevance of the technique index system. The technique index system to achieve the function of positioning is analyzed and discussed gradually. Meanwhile,the paper estimates the rationality of selected technique index system with the method of calculating relativity. Finally, the set of technique indexes to achieve the function of positioning restricted to the control of the main control station is determined. The achievement of the paper could provide the thought to design the system or test and estimate the satellite navigation system.

关键词： time & Frequency Satellite navigation System Technique in- dex.

The impact of carrier leakage and spectral asymmetry distortions on the performance of navigation signals

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The impact of carrier leakage and spectral asymmetry distort...

第三届中国卫星导航学术年会

作者： HE Cheng-yan 1,2,3 , GUO Ji 1 , LU xiao-chun 1,2 , WANG Xue 1,2 , LIU Feng 1,2,3 1 national time service center, chinese academy of sciences, No.3 Shuyuan East Road, Lintong, xi''an, Shaanxi, 710600, china 2.key laboratory for precise navigation, positioning and timing of chinese academy of sciences, Lintong, china 3 Graduate University of chinese academy of sciences, Beijing, 100190, china

In the process of analog modulation, carrier leakage will be possible if the carrier of orthogonal modulator leak to its output, with additional carrier appear at carrier frequency. What’s more, transmitter filters and power amplifier saturation may lead to spectral asymmetry. To further study the impact of these distortions on navigation signals performance, this paper begins to introduce the mechanism of carrier leakage and spectral asymmetry. Then based on a new Matlab platform and mathematical models, the impact of these distortions on signal performance is comprehensively demonstrated from different aspects from SNR （Signal-Noise-Ratio）, acquisition and tracing, to ranging accuracy, etc,. Results show that low degree of carrier leakage and spectral asymmetry won’t significantly affect signal performance, but when it deteriorates to a certain degree, the performance of navigation signals would exponentially decline. Those results and data we have obtained from this paper can also be used as a valuable reference for signal-on-board-generation designers in the process of signal design and optimization.

关键词： carrier leakage spectral asymmetry navigation signal performance affection simulation analysis

System time offset based RAIM in combined GPS/Beidou navigation system

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System time offset based RAIM in combined GPS/Beidou navigat...

第三届中国卫星导航学术年会

作者： XU Longxia1,2,3*1, LI xiaoHui1,2, XUE YanRong1,2,3, CAI ChengLin4& GUO MeiJun1,3 1national time service center, chinese academy of sciences, xi’an 710600, china 2key laboratory of Precision navigation and timing Technology, chinese academy of sciences, xi’an 710600, china 3Graduate University of chinese academy of sciences, Beijing 100039, china 4Guilin University of Electronic Technology, Guilin, 541004, china

Compatibility and interoperability of GNSS （Global navigation Satellite System） are becoming the main trend of future navigation. However, each navigation system has a time scale. When users positioning with not only one system, the time offset between them must be considered. There are several ways to acquire system time offsets. By adding unknown variables in the combined position equation to solve this variable is the commonly used way. For positioning with multi-constellations, system time offsets are some kind of burden which must be taken into account. This paper takes full use of the obtained offsets and proposes a new fault detection method for RAIM （Receiver Autonomous Integrity Monitoring）. Simulations are made to estimate the ability of this new method. This new method takes the high stability of system time offsets of GPS/Beidou system and applies it to assistant fault detection. This method has no additional requirements for navigation system and is fit for applied in receivers. It can be expected this method will be one means of RAIM for Beidou navigation system when integrated with other GNSS in future.

关键词： Compatibility and Interoperability time Offset Receiver Autonomous Integrity Monitoring Fault Detection.

基于GM(1,1)和MECM组合模型的GPS卫星钟差中短期预报

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天文学报 2018年第3期59卷 17-28页

作者：于烨张慧君李孝辉肖波陈婧亚中国科学院国家授时中心西安710600 中国科学院精密导航定位与定时技术重点实验室西安710600 中国科学院大学北京100049 中国科学院大学天文与空间科学学院北京100049

针对卫星钟差呈现趋势项和随机项变化的特点,提出了基于GM(1,1)(灰色预报模型)和修正指数曲线法(Modified Exponential Curve Method,MECM)的组合预报模型.该模型首先采用GM(1,1)预报钟差的趋势项,然后利用MECM模型对GM(1,1)残差序列进... 详细信息

针对卫星钟差呈现趋势项和随机项变化的特点,提出了基于GM(1,1)(灰色预报模型)和修正指数曲线法(Modified Exponential Curve Method,MECM)的组合预报模型.该模型首先采用GM(1,1)预报钟差的趋势项,然后利用MECM模型对GM(1,1)残差序列进行建模和预报,最后将GM(1,1)和MECM模型的预报结果相加得到钟差的最终预报值.此外,采用IGS(International Global navigation Satellite System service)公布的精密卫星钟差进行预报试验,通过与卫星钟差预报中常用的二次多项式和MECM模型预报结果的对比分析,结果表明:该方法可以对GPS卫星钟差进行高精度的中短期预报.使用12 h钟差建模时,预报6 h、12 h、18 h和24 h的平均预报精度分别为0.43 ns、0.63 ns、0.74 ns和0.79 ns,相比于二次多项式的平均预报精度分别提高了57.43%、69.71%、80.47%和86.74%,相比于MECM模型的平均预报精度分别提高了50.57%、64.41%、76.80%和84.20%;使用24 h钟差建模时,预报6 h、12 h、18h和24 h的平均预报精度分别为0.57 ns、0.61 ns、1.02 ns和1.48 ns,相比于二次多项式的平均预报精度分别提高了32.94%、55.47%、55.07%和53.16%,相比于MECM模型的平均预报精度分别提高了92.98%、66.30%、65.42%和63.99%.

关键词：天体测量学时间方法数据分析