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北斗观测值特性分析及其在PPP模糊度固定应用中的研究

发布时间:2018-03-19 16:56

  本文选题:全球导航卫星系统 切入点:北斗导航卫星系统 出处:《武汉大学》2016年博士论文 论文类型:学位论文


【摘要】:精密单点定位(PPP)技术以其计算效率高、作业灵活等优点被广泛应用。国内外学者围绕误差模型精化、PPP模糊度解算、融合惯性导航系统的PPP和单频PPP等热点问题进行了研究。在传统PPP技术的基础上,出现了PPP-RTK的概念,即利用区域或全球参考网解算改正参数,用于恢复用户模糊度的整数特性,将PPP模糊度固定为整数,从而提高实时定位精度并加快收敛速度。随着北斗系统的建设、发展和广泛应用,基于北斗观测值进行PPP并固定模糊度,有重要的科研价值和现实意义。北斗系统在星座构成、信号频率等方面有其自身特点。研究利用北斗观测值进行精密单点定位及模糊度固定,须考察北斗观测值的不同特性。本文以实现北斗PPP模糊度固定为目标,系统介绍卫星导航基本原理和方法,比较了不同PPP-RTK模型,并论证了其一致性。借助频谱分析、相关性分析和小波分析等数学工具考察了北斗MW组合观测值、伪距多路径组合观测值和无几何无电离层组合观测值中的误差及其特性,并与GPS、GLONASS和Galileo系统进行了比较。在此基础上,实现了北斗PPP模糊度固定,并开展了静态和动态PPP试验。此外,还研究了基于北斗B1/B3无电离层组合观测值的PPP及模糊度固定。本文主要研究工作如下:梳理了国内外对PPP的研究现状和发展方向,从科研价值和应用前景等方面阐述了研究北斗PPP模糊度固定的重要性。系统介绍GNSS基础理论和基本方法,在此基础上描述了PPP和PPP-RTK的数学模型。推导了两种不同PPP-RTK模型参考网和用户端的解析解,结果表明,虽然不同模型采用不同的S-变换基准和不同的改正参数向量,但不同的S-变换基准和不同的改正参数向量可以相互转换,文中给出了相应的转换关系。因此不同的PPP-RKT模型理论上是等价的。对大量测站长时间MW组合观测值的分析表明,北斗卫星的MW组合存在明显的周期性系统误差。北斗GEO卫星MW组合非整周部分的日平均值相对稳定,变换范围通常在0.2周左右,但有时会发生跳变。北斗MEO卫星MW组合非整周部分的日平均值稳定性较差,变化范围可达0.5周。北斗卫星伪距多路径组合也呈现周期性变化,变化幅度约为2 m。频谱分析和相关性分析表明,GEO卫星和IGSO卫星多路径组合的周期约为1恒星日,MEO卫星多路径组合的周期约为7个恒星日,分别与各自的轨道重复周期吻合。IGSO卫星和MEO的多路径组合与高度角明显相关,GEO卫星则无此相关性。对GEO卫星多路径组合中的周期性系统误差,进行了小波提取和改正试验,改正后伪距单点定位精度改善可达0.5 m。对于IGSO和MEO卫星多路径组合中的随高度角变化的系统误差,站间差分后可以明显消除,表明这一系统误差来源于卫星,并通过高度角模型进行了改正。北斗无几何无电离层组合相位观测值存在变化幅度约为2 cm的周期性系统误差,站间差分可以消除,表明其与卫星相关。太阳辐射和地影对无几何无电离层组合相位观测值中的误差有明显的影响。选取跟踪站组成区域参考站估计北斗卫星FCB,在用户测站开展静态和动态PPP模糊度固定试验。固定模糊度后,北斗静态PPP在E、N和U方向的RMS分别为0.8 cm、0.7 cm和2.1 cm,相比于浮点解在E和U方向分别改善了11.1%和4.5%。北斗动态PPP固定模糊度后E、N和U方向的RMS分别改善约30.4%、20.7%和10.8%,达到1.6 cm、2.3 cm和5.8 cm。BDS/GPS静态PPP固定解在E、N和U方向的RMS分别为0.4 cm、0.4 cm和0.6 cm; BDS/GPS动态PPP固定解在E、N和U方向的RMS分别为1.3 cm、1.1 cm和3.2 cm,相比于浮点解分别改善约23.5%、15.4%和8.6%。总体而言,模糊度固定对动态解精度改善更为明显,改善最明显的方向是E方向。除了定位精度,模糊度固定还可以显著改善PPP的收敛时间,固定模糊度对北斗静态和动态PPP收敛时间分别改善约4.3%和13.5%,对BDS/GPS静态和动态PPP收敛时间分别改善约16.7%和16.1%。北斗B1/B3无电离层组合精度不如B1/B2组合。实施DCB改正后,B1/B3无电离层组合PPP的精度可以显著改善;模糊度固定对B1/B3组合PPP的精度有所改善,但不明显。
[Abstract]:Precise point positioning (PPP) technology with its advantages of high calculation efficiency, flexible operation is widely used. Domestic and foreign scholars around the error model refinement, PPP ambiguity, fusion of inertial navigation system PPP and single frequency PPP and other hot issues are studied. Based on the traditional PPP technology, the the concept of PPP-RTK, namely the use of regional or global reference network solution to correct the parameters, to restore the integer ambiguity characteristics of the user, the PPP integer ambiguity, so as to improve the real-time positioning accuracy and faster convergence speed. With the construction of the Beidou system, development and wide application of Beidou observations are PPP and fix the ambiguity based on the important research value and practical significance. The Beidou System in the constellation, has its own characteristics. The signal frequency based on Beidou observations of precise point positioning and ambiguity, shall examine the compass The different characteristics of the observational data. In order to achieve the Beidou PPP ambiguity fixed target system, introduces the basic principle and method of satellite navigation, compares the different PPP-RTK model, and demonstrates the consistency. By means of spectrum analysis, correlation analysis and wavelet analysis of mathematical tools and other effects of the MW Beidou combined observations, pseudorange multipath combination observations and geometry free ionosphere free combination of error and its characteristics of observations, and GPS, GLONASS and Galileo systems were compared. On this basis, the Beidou PPP ambiguity, and the static and dynamic PPP test was carried out. In addition, also study the ionosphere free combined observations of PPP and fuzzy degree based on the fixed compass B1/B3. In this paper, the main research work is as follows: combed the research status of PPP and the direction of development at home and abroad, the research value and application prospect and other aspects of the research on Beidou PPP ambiguity Fixed importance. GNSS introduced the system of basic theory and basic methods, based on the description of the mathematical model of PPP and PPP-RTK. The solution, two different PPP-RTK model reference network and user terminal are analyzed. Results show that although the different model using correction parameter vector S- transform standard different and different, but the correct parameter vector S- transform reference different can transform each other, given the corresponding conversion relationship. Therefore theory of different PPP-RKT models are equivalent. According to the analysis of a large number of test station combinations of MW observations, the existence of the periodic system error was MW. The combination of Beidou satellite Beidou satellite GEO MW combination the whole week part of the daily average value is relatively stable, transform is usually in the range of about 0.2 weeks, but sometimes jump. Satellite MEO MW combined non integer part of a week on average stability is poor, The change range of up to 0.5 weeks. The Beidou satellite pseudorange multipath combination also showed a cyclical change, change rate is about 2 M. spectrum analysis and correlation analysis showed that the cycle of GEO satellite and IGSO satellite multipath combination is about 1 stars, MEO satellite multi cycle path combination of about 7 stars, respectively. The respective track repeat cycle multi path anastomosis and MEO combination of.IGSO satellite and GEO satellite elevation angle was significantly related, no such correlation. The periodic system errors of GEO satellite multipath combination, the wavelet extraction and correction test, corrected pseudorange point positioning accuracy can be improved to 0.5 m. with the system error the height of IGSO and MEO satellite multi path combination in angle, difference between stations can significantly eliminate, show that the system error sources in satellite, and was corrected by altitude model. Beidou without geometry electric separation Combined phase observations vary by about periodic system error of 2 cm, the station difference can be eliminated, and that the satellite. The solar radiation and the effect has obvious influence on the geometry free ionosphere free combination of phase error observations. We select the tracking stations of regional reference station estimation of Beidou satellite FCB at the station, the user to carry out static and dynamic PPP ambiguity fixing test. Fix the ambiguity, the Beidou static PPP in E, N and U directions of the RMS were 0.8 cm, 0.7 cm and 2.1 cm, compared to the float solution 11.1% and 4.5%. Beidou dynamic PPP fix the ambiguity in E and E respectively after improvement U N and U direction, RMS direction respectively improved 30.4%, 20.7% and 10.8%, up to 1.6 cm, 2.3 cm and 5.8 cm.BDS/GPS static PPP fixed solution in E, N and U directions of the RMS were 0.4 cm, 0.4 cm and 0.6 cm; BDS/GPS dynamic PPP fixed solution in E, N and U directions RMS were 1.3 cm, 1. 1 cm and 3.2 cm, respectively, compared to the float solution improved about 23.5%, 15.4% and 8.6%. overall, ambiguity on the dynamic precision of the solution improvement is more obvious, the most obvious improvement direction is E direction. In addition to the positioning accuracy, ambiguity can significantly improve the convergence time of PPP, fixed ambiguity of Beidou the static and dynamic convergence time of PPP were improved by approximately 4.3% and 13.5% of BDS/GPS, the static and dynamic convergence time of PPP were improved about 16.7% and 16.1%. Beidou B1/B3 ionosphere free combination accuracy than B1/B2 group. The implementation of DCB corrected B1/B3 ionosphere free combination of the accuracy of PPP can significantly improve the accuracy of fixed; fuzzy B1/B3 combined PPP has improved, but it was not obvious.

【学位授予单位】:武汉大学
【学位级别】:博士
【学位授予年份】:2016
【分类号】:P228.4


本文编号:1635165

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