【作者】 张鹏；

【导师】 刘经南；

【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】 地球参考框架(TRF)是地球参考系统(TRS)的实现,是全球地心坐标系建立的基础,其动态过程能反映全球变化信息,诸如地球板块运动、海平面变化,地下水位变化等。研究地球参考框架的建立与维持对经济与社会发展具有重要的科学与现实意义。本文综述了坐标系统的定义及实现理论基础,分析了影响坐标参考框架实现的主要因素,研究了中国大陆板块运动特征,获得了国家GNSS连续运行基准站水平速度场和垂直速度场,并开展了GNSS基准站坐标时间序列分析研究。论文的主要工作和贡献为：1)系统地综述了坐标系统的定义与实现的理论基础,并分析了影响坐标框架实现的主要因素。论文介绍了国际地球参考系统(ITRS)建立的方法,概述了国际地球参考框架(ITRF)的发展历程,重点讨论了区域参考框架EUREF及SNARF的实现及发展现状,在此基础上,分析了影响坐标框架实现的主要因素等。2)采用欧拉模型、GPS实测速度及拟合模型确定了中国大陆地壳运动速度场,并研究了中国大陆应变场。论文概述了国际上较为成熟的四种板块运动模型,并通过欧拉模型、GNSS实测速度场和拟合模型获得了中国大陆地壳运动速度场。在此基础上对中国大陆应变场进行了研究,分析NUVEL-1A模型在中国应用中的问题,研究并比较了相似变换方法及欧拉矢量方法求解GNSS基准站的运动速度一致性,结果表明都能很好的反映中国大陆地壳运动特征。3)通过分析中国国家GNSS基准站以及GNSS大地控制网,获取了中国34个国家基准站、1630个GPS控制点的坐标与速度场成果及基准站时间序列。论文介绍了我国自上世纪八十年代开始建立的各类全国范围的GPS网情况,以及与ITRF框架的关系。对目前国家GNSS基准网11年的连续观测数据,以及GNSS大地控制点多期的数据进行了全面处理,详细阐述了数据源、基准站选取、数据处理策略、整体平差的方法与精度统计,获得了目前国内34个国家基准站、1630个GNSS大地控制点完整的成果,包括坐标、速度场、基准站时间序列等。4)研究了国家GNSS基准站周解时间序列的线性及周期特性,分析了我国地心坐标参考框架的稳定性,为中国地心坐标参考框架的维持提供了理论基础和实际指导意义。论文通过对多年累积的国家GNSS基准站网整体解的坐标及速度精度进行了统计分析,讨论了长期和短期框架的稳定性、实时性和动态性,给出了我国地心坐标参考框架精确性的量化指标,揭示了中国区域坐标参考框架的实时性和动态性。并通过对国家GNSS基准站周解时间序列的分析获得了基准站的线性及非线性运动特征,结果表明：基准站水平分量时间序列的总体变化趋势基本上为线性变化,各点变化的大小和方向与板块运动、板内运动相关；高程方向的运动呈现近似于正弦函数的结果,周期约为1年,且高程方向周期性运动的能量在三个方向周期性运动总能量中占有很大的比重,是影响高程精度的主要因素之一。5)利用主成分空间滤波算法(PCA)分析了国家GNSS基准站网坐标时间序列中公共误差的时空特性,有效地减少了大尺度因素对CORS站坐标时间序列的周期性影响。论文采用主成分空间滤波算法(PCA)去除了中国国家CORS网的公共误差,有效降低了大尺度因素对CORS站坐标时间序列的周期性影响,提高了中国GNSS基准站本地信号的信噪比。结果表明：通过滤波后,北、东和高方向的平均均方差相对于滤波前分别减小了26%、22%和36%。6)采用功率谱和极大似然估计方法分析了国家CORS基准站坐标时间序列的噪声特征,发现白噪声、闪烁噪声和随机游走噪声是基准站坐标时间序列的基本噪声特征。论文利用功率谱和极大似然估计方法比较分析了主成分空间滤波前后国家GNSS基准站近10年坐标时间序列的噪声特征,发现滤波后的国家CORS站在水平和高度分量上均表现出不同的噪声性质,白噪声、闪烁噪声和随机游走噪声是国家CORS基准站坐标时间序列的噪声基本特征,且结果显示高程分量的有色噪声估值明显大于水平分量。同时,分析了产生有色噪声的可能主要来源,认为高阶电离层误差足CORS站有色噪声的主要来源,并根据不同噪声模型得到了基准站速度及精度,结果表明顾及有色噪声的速度误差估值比只考虑白噪声的速度误差估值一般大2～4倍,两种噪声模型的速度估值偏差一般在5%～10%左右。因此认为可变白噪声加有色噪声模型更加符合中国国家基准站实际运动特征。更多还原

【Abstract】 As the realization of Terrestrial Reference System (TRS), Terrestrial Reference Frame (TRF) is the basis of the establishment of the globle geocentric coordinate system. The dynamic process of TRF can reflect important information on globle changes such as plate motion, change of the sea level, change of underground water and so on. Research on establishment of TRF has significant meanings on the development of the economy and the society no matter in the field of science or reality.This article summarizes the definition and basis theories of coordinate system, analyses the main factors that have impact on the realization of coordinate system, researches the feature of plate motion of Chinese mainland, acquires the horizontal and vertical velocity fields of the national GNSS Continuously Operating Reference Stations(known as CORS), and does some analysis on time series of GNSS station coordinates. The main achievement and contribution of this paper is:The article introduces the establishment methods of International Terrestrial Reference System (ITRS), and the development of International Terrestrial Reference Frame(ITRF), mainly discusses the realization and development actuality of regional reference frame EUREF and SNARF. On basis of this, it analyses the main impact factors of coordinate fame realzation.The article give brief of4kinds of plate motion models, and acquires the velocity fileds in Chinese mainland by using Euler Model, GPS actual measurement and its fitting model. The realted research was carried out, for example NUVEL-1A model in China, comparison the consistency of similarity transformation and Euler vector model methods. It turns out that the two methods can reflect the motion feature of Chinese mainland very well.In this paper, brief introdution of various GPS networks, which were established in1980s in China individually which have good relationship with ITRF. Currently, there are continuous and abounant observation data in last11years. This paper give more detail about data resources, selection principle of base stations, strategies of data processing, adjustment method and statistics. The final results invole34national base stations and1630GNSS geodetic control points.Based on the resut of time series of national GNSS base stations, this paper discusses the stability, instantaneity and dynamism of both frame in long and short periods, and indicate accurate quantified indicators of TRF in China. Through analysis of time series of national GNSS base stantion’s weekly solutions, it obtains linear and nonlinear motion feature of the fiducial stations. The result shows that time series of horizontal vector have linear changes generally, and the quantity and direction of these changes is related to plate movement and relate movement between different plates; vertical motion shows result of a sinusoidal function with annual period. The power of periodic motion in vertical direction is bigger than it in horizontal direction and it is one of the main factors that impact on vertical accuracy.This paper introduce Principle Componant Analysis (PCA) method to eliminate the common error in the national CORS network, which effectively reduce the impact of the large scale factors on time series and improve the signal ratio. Result shows that after PCA filtering, the average mean square error in the N, E, and U reduced by26%,22%and26%respectively compared to the value before the filtering.The paper give the result of different noise character on10years time series before and after the filtering using the method of power spectrum and maximum likelihood estimation. Finally, it shows that noise characteristic are different in the orientation of the horizon and the height of the national CORS network, and the white noise, flicker noise and random walk noise are the basic characteristics in the coordinate time series, and the colored noise in the vertical component is bigger than the horizontal component obviously. In this paper, the analysis of colored noise source shows that higher-order ionosphere errors are the main source. Introducing different noise model to velocity and its precision estimation, the comparison result between colored noise and white noise shows that elocity evaluation bias is generally around5%～10%, the error is amplified2～4times. So the conclusion is that variable white noise plus color noise stretagy are more suitable with actual motion characteristics of national base stations.更多还原