【作者】 胡志刚；

【导师】 刘经南； 赵齐乐；

【作者基本信息】 武汉大学 ， 大地测量学与测量工程， 2013， 博士

【摘要】 卫星系统性能评估是卫星系统初期设计、研发和部署以及系统升级扩展的主要依据之一,也是卫星系统连续运营重要保障。我国的北斗卫星导航系统采取“先试验、后区域、再全球”的三步走战略,各个阶段的卫星星座设计、性能指标、服务范围等既有承前启后、平稳过渡的作用又有各自特色。因此研究适合于北斗系统的性能评估理论与方法对现阶段的区域系统和将来覆盖全球的北斗卫星系统发展具有重要的现实意义。本文以建立北斗卫星导航系统性能评估体系为目标,系统研究卫星导航系统的基本理论、模型、方法,并自主设计进而研制了以北斗系统为主、兼顾GPS、GLONASS、Galileo的性能评估软件系统,实现了从空间信号层到服务层性能综合评估的较为完善的体系。在此基础上,通过分析处理北斗系统试运行以来的海量实测数据,按系统星座结构变化分阶段对比分析了北斗区域系统基本的性能提升过程,进一步验证了北斗系统性能评估理论、方法和软件系统的正确性。从影响高精度定位的载波观测值的数据质量入手,对比分析相同环境下北斗系统与GPS的载噪比、多路径和噪声水平；开展了短基线相对定位和精密单点定位试验,分析了北斗高精度定位的性能水平。本文主要研究工作及贡献如下：1、分析总结了GPS、GLONASS和Galileo导航卫星系统性能评估国内外研究现状。从完善现有导航系统的评估理论和方法以及我国北斗卫星系统发展的需求出发,阐述了北斗卫星系统性能评估的理论方法研究和软件研制的必要性。2、系统研究了以GPS为代表的GNSS卫星系统性能评估基本理论与方法。重点论述了GNSS卫星导航的必备性能指标,包括可用性、精度、完好性和连续性指标定义及相关计算方法。3、提出了适用于北斗系统空间信号精度的计算方法。北斗区域卫星系统的最大特点是卫星星座主要以GEO和IGSO地球同步轨道组成,其轨道高度的不同导致已有的空间信号误差URE精度计算方法失效。本文对北斗URE精度的统计公式进行了详细推导,同时详细分析论证了北斗用户距离率误差URRE和用户测距加速度的计算方法。然后对实测数据进行了评估,分析得出URE优于1.5米：URRE优于3.00mm/s; URAE优于2.00mm/s2。4、基于武汉大学“北斗试验跟踪网”观测数据,利用PANDA精密定轨软件获取的精密钟差数据在轨评估了北斗导航星时钟频率稳定度。卫星钟作为导航系统的星上时间基准,是卫星导航系统的核心部分,其性能将直接影响系统的服务精度。本文依靠有限的数据资源利用北斗精密钟差数据综合评估了北斗频率稳定度。北斗在轨卫星大部分原子钟分钟稳定度分钟稳定度达到1-2×10--2,千秒稳达3-4×10-13,万秒稳定度达1-2×10-13量级,天稳定度可达1-2×10-1‘量级。北斗铷钟稳定度水平与GPSBlock Ⅱ A的铷原子钟、GLONASS-M卫星和日本的QZSS星载原子钟性能水平相当,优于GPS Block ⅡA的铯钟,而略差于Block ⅡR铷钟和Galileo铷钟。5、首次系统分析了北斗空间信号误差的统计特性。利用统计学中的峰度和偏度系数以及Q-Q图对北斗空间信号误差进行正态假设的验证,同时对不同卫星之间的误差相关性进行了假设检验。结果表明北斗空间信号误差分布并不严格服从零均值正态分布,而更接近于学生分布。同时,统计结果表明不同卫星之间的误差相关性很弱。6、统计分析了自2011年北斗系统试运行以来的PNT性能。本文基于“北斗实验网”对分布在亚太地区的典型监测站的PNT性能进行了分析计算(2012年1月-2013年6月).评估结果表明这些监测站附近北斗系统单频伪距单点定位服务精度已满足北斗服务区内的服务指标。7、利用本文提出的PNT性能预测方法对北斗当前为区域系统的情况下对服务区内的PNT进行预测,并用实测监测站的数据进行了复核。推算的结果表明,当前北斗系统在中国地区的PDOP值分布大部分达到3～5,三维定位精度优于10米；但范围扩大到整个亚太地区时,在精度处于东经80。和140。开外的大部分地区达不到10米的定位水平；然后针对将来的北斗全球导航系统(3G+3I+27M)星座下的DOP值分布和可能达到的PNT性能进行简单预测,结果表明HDOP将优于1,而VDOP将优于2.0,水平精度优于3米,高程可达4-5米。这一结果表明,2020年建成的北斗系统的PNT性能将与当前GPS相当。8、首次实现了北斗室外绝对天线相位中心算法并评估了北斗高精度定位性能。本文深入研究了基于机器人的绝对天线相位中心校正理论与方法,并通过实测数据分析与GPS已知天线相位中心进行比较,取得了优于lmm的外符合精度。基于该技术估算的北斗天线相位变化消除了其对北斗高精度定位性能评估的影响。基于该项成果,本文对比分析相同环境下北斗系统与GPS观测数据质量,然后开展了短基线相对定位和精密单点定位的性能测试。结果表明,北斗系统的短基线相对定位可到mm级,精密单点PPP可达到cm级的定位水平,定位性能与GPS基本接近。9、以北斗性能评估为主,兼顾GPS和Galileo系统,自主设计并研制了卫星导航系统性能评估软件系统,主要研究内容包括：软件总体框架、功能模块、算法流程等。更多还原

【Abstract】 The assessment of the satellite system performance is not only one of the main basis for the satellite system initial design, research and development, deployment and system upgrade extensions, but an important guarantee for the satellite system continuous operation. In China, BeiDou Navigation Satellite System (BDS) adopts the three-step strategy of "first test, then the area, and last the world". The design of satellite constellation, the performance index, the scope of services of the various stages have the function of connecting the past and future and smoothing transition, which also have its own characteristics. So researching on the theory and method for the evaluation of the BeiDou system performance has an important practical significance for the development of the regional system at the present stage and the future global coverage of the BeiDou satellite system.With the goal of establishing the BDS performance evaluation system, this paper systematically studies the basic theory, model and method of the satellite navigation system, and also designs and develops a software system mainly on the evaluation of the BeiDou system performance, which also contains the evaluation of the Galileo and GPS performance, achieving a relatively perfect performance evaluation system from the spatial signal aspects to the service aspects On this basis, this paper analyzes and processes the BeiDou system massive measured real data since the trial operation, compares and analyzes the basic properties of the ascension process of the BeiDou regional system according to the change of the system constellation structure, which further verified the theory, method and software system of the BeiDou system performance evaluation. Finally, starting with the impact of the data quality of the high-precision positioning carrier observation, this paper comparatively analyzes the carrier to noise ratio, multipath and noise levels of the BeiDou system and GPS under the same environment; and then carried out a short baseline relative positioning and precise point positioning testing to analyze the precision positioning performance levels of BDS. The main research work and contributions in this paper are as follows:1. The research status is analyzed and summarized about the performance evaluation of GPS, GLONASS and Galileo navigation satellite system. The necessity of the theory research and software development of the BeiDou satellite system performance evaluation is stated to improve the existing navigation system assessment theories and methods as well as the BeiDou satellite system development needs and expounds.2. Starting from the definition of performance, the basic theory and method are studied about the evaluation of GNSS satellite system performance with GPS as the representative. The essential performance index of GNSS satellite navigation is focused on, including availability, accuracy, integrity and the definition of indicators of continuity and related calculations. 3. Using the theory and method of the performance evaluation in this research, a software system of the satellite navigation system performance evaluation is designed mainly to evaluate the BDS performance, also containing GPS and Galileo system, including the main research contents:general framework of the software, function module, algorithm flow etc..4. The calculation method is proposed suitable for the accuracy of the BeiDou System spatial signal. The obvious characteristic of the BeiDou system is a constellation of satellites mainly consisted of GEO and IGSO geosynchronous orbit. The different height orbit results in the failure of the existing calculation method of spatial signal error of URE precision. This paper deduces the statistical formula on the URE precision in detail, and demonstrates the calculating method of BeiDou user range rate error (URRE) and user range acceleration error (URAE). After the assessment of the measured data, results show that URE is better than1.5meter; URRE is superior to3.00mm/s; URAE is superior to2.00mm/s2.5. The clock frequency stability of the on-board BeiDou navigation satellite is assessed for the first time using the precise clock offset data from the BeiDou precise orbit determination. Satellite clocks as the time basis of navigation system onboard is a core part of the satellite navigation system, whose performance will directly affect the accuracy of the system services. This paper firstly uses the limited data and the precision clock difference data comprehensive assessment the frequency accuracy, frequency and frequency stability of the BeiDou clock, getting the stability of1-2×10-12per60s,1-2×10-13per10000s,and1-2×10-14per day, which is considerable with GPS Block IIA atomic clock performance levels.6. The statistical properties of the BeiDou spatial signal error are full analyzed for the first time. Using the coefficients Kurtosis and Q-Q plot in statistics test the normality assumption of the BeiDou spatial signal error, while testing correlation of the error between different satellites with hypothesis testing.7. The Positioning and Navigation and Timing(PNT) performance is statistically analyzed since2011the BeiDou system trial operation. In this paper, based on the "BeiDou network", the PNT performance of the typical monitoring station on the distribution in the Asia Pacific region is analyzed (January in2012-June in2013). The assessment results show that the accuracy of the BeiDou system single-frequency pseudo range point positioning near these monitoring stations has been met the BeiDou provided services index within the service level10meters in horizontal and10meters in elevation.8. The PNT performance in the service area is predicted using the method proposed in this paper on the current regional BeiDou system, checked using measured data at the monitoring stations. The calculated results show that most of the PDOP value is3to5and three-dimensional positioning accuracy is better than10meters on the current BeiDou system in China; while the scope expands to the entire Asia Pacific region, the longitude in the east longitude80°and140°most areas, the positioning level is not up to10meters. Then this paper simply predicts the DOP values and the PNT performance in view of the future BeiDou global navigation system (3G+3I+27M) constellation.9. The high-precision positioning performance of BDS is analyzed. In this paper, the observation data quality of BDS and GPS are analyzed under the same environment; and the performance of the short baseline positioning and precise point positioning are tested. Results show that the PPP positioning level of BDS can achieve cm level, which is close to the GPS performance level.10. It is the first time to achieve BDS absolute outdoor phase center variation technology. Phase center variation must be considered for high precision application. This article studies the theory and methods for the absolute robot-based phase center variation, and analyzes the measured data compared with the known GPS antenna phase center, which shows consistency better than1mm. This result indicates that China has initially mastered the key technology of outdoor absolute antenna phase center variation for high-precision BeiDou applications.更多还原