BDS在轨卫星钟特征分析、建模及预报研究

发布时间：2018-05-11 05:22

  本文选题：BDS + 在轨卫星钟　； 参考：《武汉大学》2016年博士论文

【摘要】：我国从2004年开始启动北斗卫星导航系统建设,经过8年研发,顺利完成区域导航卫星星座组网,并于2012年12月27日对外宣布提供区域导航、定位、授时服务。按照三步走计划,我国将在2020年前后建成覆盖全球的卫星导航系统。GNSS系统性能与卫星钟性能以及系统对卫星钟特征参数的估计和预报能力密切相关。卫星钟作为GNSS系统的关键设备,是获取高精度时频信息的前提和条件。对北斗在轨卫星钟特征进行分析,并开展相应的卫星钟差预报研究,是一项具有理论意义和实用价值的研究课题,对于理解北斗系统服务现状,讨论北斗系统服务性能优化或改进方法具有重要意义。与地面原子钟不同,导航卫星原子钟特征分析和预报具有自己的特点：首先,卫星原子钟特征分析数据不能直接获取,卫星原子钟特征分析通常采用由星地时间比对算法估计的卫星钟差数据,该数据不仅包含卫星钟的影响,还受到时间比对算法的影响；其次,由于运行环境的不同,导航卫星原子钟受卫星轨道动力学环境的影响。星地时间比对算法包括单向和双向两种方式,常用的单向时间比对技术为ODTS技术,双向时间比对技术为TWTT技术。BDS系统采用TWTT技术进行卫星时间与地面系统时间的同步,具有创新性和独特性。TWTT技术与ODTS技术的不同主要体现在观测数据类型、数据处理策略以及算法时间基准等方面,两种技术估计的卫星钟钟差数据具有各自不同的特点：与ODTS钟差相比,TWTT钟差受卫星轨道误差的影响较小。两种钟差数据的对比分析,对于识别BDS卫星轨道及卫星钟差估计误差,进而提高其估计精度具有重要意义。目前,国内外对BDS卫星钟的特征分析主要集中在系统特征和随机特征两个方面,采用的数据量普遍较少,分析时间段普遍较短,尚未开展BDS卫星钟周期变化特征及其原因的分析工作。TWTT技术是BDS系统的创新,目前利用TWTT钟差与ODTS钟差进行BDS卫星钟特征分析的工作仍然较少。国内在卫星钟差预报方面的研究主要集中钟差预报函数模型组合、钟差随机分量的数学方法建模等方面,在卫星钟随机特征对卫星钟差预报模型参数估计误差的影响方面以及卫星钟预报性能分析方面的研究工作相对较少。本文以BDS卫星钟在轨性能评估为主要目标,以在轨特征分析为主要内容,以提高BDS卫星钟差预报精度为主要目的,利用ODTS及TWTT钟差数据,对BDS卫星钟的系统特征、周期变化特征、随机特征以及可预报性能进行分析,结合BDS卫星钟差预报现状,讨论BDS钟差预报精度优化及改进的相关方法,对BDS系统性能优化及改进具有一定的创新性和应用价值。本文主要研究内容和成果包括：1)总结了导航卫星钟差估计、特征分析及预报理论与方法研究现状,分析讨论了ODTS及TWTT钟差在BDS卫星钟特征分析、建模的作用,明确了BDS卫星钟特征分析、建模及卫星钟差预报误差特性分析对BDS系统服务性能优化和提升的重要性和必要性；2)研究了精确时间信息在GNSS系统中的生成与传递；分析了当前常用的卫星钟差估计算法及其数据处理策略对卫星钟差估值产生的影响；从卫星钟特征分析、建模及预报的角度出发,确定了本文的特征分析方案及与卫星钟差预报有关的研究内容;3)讨论了ODTS定轨策略对卫星钟差估计的影响；分析了WHU-BDS精密钟差的内符合精度及与其他分析中心精密钟差的符合程度；基于ODTS钟差数据,分析了BDS卫星钟的系统特征,讨论了GEO/IGSO卫星轨道长半轴变化对BDS卫星钟频漂的相对论影响；分析了BDS卫星钟周期变化特征,研究了卫星钟差周期变化特征与卫星动力学环境的相关性,讨论了BDS卫星钟周期变化的原因；分析了BDS卫星钟亚天频率稳定性及其时变特征,幂律噪声类型以及噪声水平等随机特征,从频率稳定性角度出发,给出了BDS卫星钟的稳定性分析参数；4)分析了TWTT钟差的内符合精度,讨论了TWTT钟差与ODTS钟差差异的周期变化与卫星轨道之间的相关性,得出了ODTS钟差受卫星轨道误差影响的结论；基于TWTT钟差数据,分析了BDS卫星钟的系统特征、周期变化特征及随机性特征；对比分析了TWTT中差与ODTS钟差数据特征及其相应的BDS卫星钟特征分析结果：5)基于卫星钟特征分析结果,定义了BDS卫星钟系统的随机微分方程,推导了该微分方程的Kalman滤波解,该系统能够顾及多种随机噪声以及卫星钟周期变化的影响；分别以ODTS钟差和TWTT钟差为观测量,利用Kalman滤波算法估计卫星钟状态,取得了良好结果；利用Kalman滤波算法,实现了ODTS钟差和TWTT钟差数据的融合；6)评价了BDS广播星历钟差精度,从理论角度分析了广播星历钟差预报精度改进的相关方法;进行了BDS卫星钟差滑动拟合、预报实验,讨论了多项式模型参数估计误差对BDS卫星钟差预报误差的影响；在此基础上设计了BDS卫星钟差混合区间拟合预报策略；以周期项对拟合、预报结果的影响为评价标准,讨论了周期项参数在BDS卫星钟拟合、预报数学模型中的显著性。
[Abstract]:China started the construction of the Beidou satellite navigation system from 2004. After 8 years of research and development, we successfully completed the network of regional navigation satellite constellations, and announced the regional navigation, positioning, and time service in December 27, 2012. According to the three step plan, China will be built into the global satellite navigation system.GNSS system performance before and after 2020 and the performance of the satellite navigation system. The satellite clock performance and the system are closely related to the estimation and prediction of the characteristic parameters of the satellite clock. As the key equipment of the GNSS system, the satellite clock is the prerequisite and condition for obtaining high precision time frequency information. It is of theoretical significance and reality to analyze the characteristics of the Beidou on orbit satellite clock and to carry out the corresponding satellite clock difference prediction research. The research topic of value is of great significance for understanding the present situation of the Beidou system service and discussing the optimization or improvement method of the Beidou system service performance. Unlike the ground atomic clock, the characteristics analysis and prediction of the navigation satellite atomic clock have its own characteristics: first, the analysis data of the satellite atomic clock can not be obtained directly, and the satellite atomic clock is not available. Feature analysis usually uses satellite ground time comparison algorithm to estimate satellite clock difference data. This data not only contains the influence of satellite clock, but also influenced by time comparison algorithm. Secondly, the navigation satellite atomic clocks are affected by the dynamic environment of satellite orbit because of the different operating environment. The algorithm of satellite earth time comparison includes unidirectional and two-way. Two ways, the common one way time comparison technology is ODTS technology, the bidirectional time comparison technology is TWTT technology.BDS system using TWTT technology to synchronize the time of satellite time and ground system time. It is innovative and unique, the difference between.TWTT technology and ODTS technology is mainly embodied in the observation data type, the data processing strategy and the algorithm. The satellite clock clock difference data estimated by the two technologies have their respective characteristics: compared with the ODTS clock difference, the TWTT clock error is less affected by the satellite orbit error. The contrast analysis of the two clock difference data is of great significance for identifying the BDS satellite orbit and the satellite clock error estimation error and thus improving the estimation accuracy. The characteristics of BDS satellite clocks at home and abroad are mainly focused on two aspects of the system features and random characteristics, and the data is generally relatively short, the analysis time is generally short, and the analysis of the BDS satellite clock cycle change features and its causes is not carried out..TWTT technology is the innovation of the BDS system. At present, the TWTT clock difference and the ODTS clock difference are used to carry out BD The work of the S satellite clock feature analysis is still less. The domestic research on satellite clock difference prediction mainly focuses on the combination of clock difference prediction function model and the mathematical modeling of the clock difference random component, and the influence of the satellite clock random characteristics on the estimation error of the satellite clock difference prediction model and the performance analysis of the satellite clock prediction. The research work of the BDS satellite clock is relatively small. This paper takes the orbit performance evaluation of the BDS satellite clock as the main goal, taking the orbit characteristic analysis as the main content, in order to improve the accuracy of the BDS satellite clock difference prediction, and uses the ODTS and TWTT clock difference data to classify the system features, the periodic variation characteristics, the random characteristics and the predictability performance of the BDS satellite clock. In the light of the status of the BDS satellite clock error forecast, this paper discusses the methods of optimizing and improving the precision and improvement of the BDS clock error forecast. It has some innovation and application value for the performance optimization and improvement of the BDS system. The main contents and achievements of this paper are as follows: 1) the estimation of the clock difference of the navigation satellite, the characteristic analysis and the research status of the theory and method of prediction are summarized. The analysis of ODTS and TWTT clock difference in BDS satellite clock characteristics analysis, the role of modeling, the analysis of BDS satellite clock characteristics, modeling and satellite clock error prediction error characteristics analysis of the BDS system service performance optimization and promotion of the importance and necessity; 2) study the generation and transmission of accurate time information in the GNSS system; analysis of the present The influence of satellite clock difference estimation algorithm and data processing strategy on satellite clock difference estimation; from the angle of satellite clock feature analysis, modeling and prediction, the feature analysis scheme and the research content related to satellite clock difference prediction are determined. 3) the influence of ODTS orbit determination strategy on satellite clock error estimation is discussed. The internal coincidence precision of WHU-BDS precision clock difference and the degree of coincidence with the precision clock difference of other analysis centers are analyzed. Based on the ODTS clock difference data, the system features of the BDS satellite clock are analyzed. The relativistic influence of the long half axis change of the GEO/IGSO satellite orbit to the BDS satellite clock frequency drift is discussed. The characteristics of the BDS satellite clock cycle change are analyzed and the satellite is studied. The correlation between the periodic variation of clock difference and the dynamic environment of satellite is discussed. The reasons for the clock cycle change of BDS satellite are discussed. The random characteristics of the BDS satellite clock frequency stability and its time-varying characteristics, power law noise type and noise level are analyzed, and the stability analysis parameters of the BDS satellite clock are given from the angle of frequency stability; 4 The internal coincidence accuracy of the TWTT clock difference is analyzed, the correlation between the difference between TWTT clock difference and the ODTS clock difference and the satellite orbit is discussed. The conclusion that the ODTS clock difference is influenced by the satellite orbit error is obtained. Based on the TWTT clock difference data, the system characteristics, the periodic variation and the randomness of the BDS satellite clock are analyzed, and the T is analyzed and compared with the T. The data characteristics of difference and ODTS clock difference in WTT and its corresponding BDS satellite clock feature analysis results are as follows: 5) based on the result of the satellite clock feature analysis, the stochastic differential equation of the BDS satellite clock system is defined and the Kalman filtering solution of the differential equation is derived. The system can take account of the influence of a variety of random noise and the change of the satellite clock cycle; OD TS clock difference and TWTT clock difference are measured. The Kalman filter algorithm is used to estimate the satellite clock state, and good results are obtained. Using the Kalman filtering algorithm, the fusion of ODTS clock difference and TWTT clock difference data is realized; 6) the accuracy of the clock difference of the BDS broadcast ephemeris is evaluated, and the related methods for improving the accuracy of the clock difference prediction accuracy of the wide broadcast ephemeris are analyzed from the theoretical angle. The effect of the BDS satellite clock difference sliding fitting, the prediction experiment, the influence of the parameter estimation error of the polynomial model on the prediction error of the BDS satellite clock difference is discussed. On this basis, the fitting prediction strategy of the BDS satellite clock difference mixing interval is designed. The influence of the periodic term on the fitting and the prediction results is the evaluation criterion, and the periodic term parameters are discussed in the BDS satellite. The fitting of the clock is used to predict the significance of the mathematical model.

【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
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本文编号：1872568