【作者】 张西光；

【导师】 吕志平；

【作者基本信息】 解放军信息工程大学 ， 测绘科学与技术， 2009， 博士

【摘要】 地球参考框架是地球参考系的实现,习惯上称为大地坐标系,或者称为大地基准,是大地测量的基础,一直是大地测量中最基本的问题。大地测量的主要任务之一是测量和绘制地球的表面形状。为了表示、描绘和分析测量成果,必须建立大地坐标系。本文主要从数据处理角度出发,探讨地球参考框架建立的本质,以及建立现代地球参考框架的约束种类和处理方法;讨论了现在已经建立的地球参考框架的原点、尺度、定向、及其时间演化的实质,即如何认识现有的参考框架;研究了地球参考框架的维持问题,对我国建立基于GNSS的参考框架的基本问题给出了建议。本文研究的基本结论如下:一、确定参考框架的问题,实质上就是完成控制网的定位。定位控制网需要七个参数,3个平移参数、3个旋转参数和尺度参数,建立动态的参考框架则还需要上述七个参数的速率参数,共14个参数。从大地测量的观点看,这14个参数可以看做两个TRF之间的相对值,其选择应当满足所采用的TRS定义。二、自由网平差是一种可以保持控制网最佳网形的数据处理方法。在空间大地测量阶段,松约束方法更方便应用。算例证实,在一个相当宽的数值范围内,松约束法有很好的数值稳定性,且松约束方法的解与自由网附加条件法解等价。保持控制网最佳网形的各种数据处理方法,又都可以归为最小约束一类。最小约束可以认为是提供了分析解算的充分必要数据或约束条件,使得处理结果能够保持控制网由观测得到的最佳网形。一般的,任何解集,这里指解的方差协方差矩阵,都可以化分为内部噪声和参考系效应。三、ITRF2000原点所实现的本质在长期上近似为CM,在季节性和其它的短时间尺度上为CF。在ITRF2000之前,以前版本的ITRF原点实现的本质在所有的时间尺度上近似为CF。ITRF2000在1mm/a的精度水平内,与NNR-NUVEL1A是匹配的,即满足NNR条件。精细、科学的全球板块运动模型对更好地实现NNR条件是很重要的。PB2002边界模型就是一个更精细的模型,受此启发,对建立我国构造地块的边界模型给出建议。四、所谓参考框架的维持,就是指给出点位随时间变化的坐标。维持参考框架的技术手段主要有两种,一种是给出台站速率,一种是利用空间大地测量技术给出台站的实测坐标时间序列,而后一种是多数地区维持区域参考框架的选择。五、针对GNSS的参考框架,是GNSS做的所有事情的基础,因而需要特别的关注。IGS实现的长期参考框架IGS00是较ITRF更为精密的参考框架,是IGS产品的基础。GSGP也要实现基于Galileo系统的GTRF。我国北斗二代关于参考框架的设计和实现可借鉴IGS和GGSP的经验。更多还原

【Abstract】 Terrestrial reference frame (TRF) is the realization of terrestrial reference system, customarily called geodetic coordinate system or geodetic datum. TRF is the foundation of geodesy. Also, it has always been the fundamental problem of geodesy. The main task of geodesy is to deal with the measurement and representation of the Earth. Geodetic coordinate system is indispensable to represent and analyze the results of surveying. This paper reviews the nature of establishment of TRF, constraint types and their processing methods in establishing modern TRF. The nature of origin, scale, orientation, and their time evolution of current ITRF is discussed in order to understand it better. In addition, the maintenance of TRF is researched. Some suggestion is given on how to establish reference frame of GNSS of China.The conclusions of this paper are as follows:1. The nature of establishment TRF is to realize the positioning of geodetic control network. The positioning of a control network requires seven parameters, three translation components, one scale factor, and three rotation angles. If a dynamic reference frame is to be established, another seven parameters is needed, i.e., seven rates of the above components. From a geodetic point of view, the 14 parameters should be viewed as relative values between two TRFs, their selection should correspond to the adopted TRS definition that one wants to satisfy.2. Free network adjustment is a method that can conserve the best shape of control network only determined by observations. Loose constraint, as a method of free network adjustment, is suitable and convenient for spatial geodetic technique. A simple example has approved that there is a quite wide range of value, in which loose constraint solution is identical to free network solution. Various methods conserving the best shape of control network can be classified as minimum constraint. Minimum constraint provides sufficient and essential data for adjustment, which conserves the properties of the observing technique. Generally speaking, any solution can be identified into two parts: an internal noise in an observation and the reference system effect.3. The realized nature of the ITRF2000 origin becomes CM in the long term, but CF on seasonal and short timescales. Before ITRF2000, the realized nature of previous ITRF origins was not CM but approximately CF on all timescales due to an incomplete kinematic model under a CF frame. ITRF2000 is aligned with NNR-NUVEL1 A at 1 mm/a level, i.e., it satisfies NNR condition. An elaborate and scientific global plate kinermatic model is very important for realizing NNR condition, which states that the integral over the Earth’s surface of all plate motions should be zero. Plate boundary model, being a more elaborate model than ever, inspires us to give some considerations on establishment of plate boundary model in China.4. Simply speaking, the maintenance of terrestrial reference frame is to provide coordinates of points varying with time, taking the form of velocity model or of coordinate time series in general. As for as the maintenance of regional reference frame, the latter is preferred.5. The reference frame must be recognized as the foundation of everything the GNSS does and therefore deserving of special attention. IGS00, the IGS long-term frame realization, is a frame of more accuracy than ITRF and is the basis of IGS products. GGSP (Galileo Geodetic Service Provider Prototype) is researching to realize Galileo TRF based on Galileo system. There is some experience for the design and construction of BeidouⅡreference frame.更多还原