GPS精密测量中的海潮负荷问题研究

发布时间：2018-06-22 11:28

本文选题：GPS + 海潮模型　；参考：《武汉大学》2014年博士论文

【摘要】：以GPS (Global Positioning system)为代表的现代空间定位技术手段的蓬勃发展和广泛应用,近20年来积累了大量的宝贵原始观测数据,也为大地测量和地球物理等地学研究领域开辟了广阔的前景。高精度和高可靠性的GPS数据处理结果是地学研究的基础,海潮负荷位移改正对提高GPS估计精度已经得到了广泛的共识,也为GPS坐标时间序列研究中剥离海潮负荷效应影响提供了有效途径,同时利用GPS坐标时间序列分析可以检验海潮负荷模型的精度和适应性。因此在GPS精密测量中研究海潮负荷效应对大地测量和地球物理学研究获取准确的几何和物理信息具有重要的理论意义和参考价值。本文系统地阐述了GPS精密测量中海潮负荷效应在国内外的发展现状和趋势,分析了海潮负荷影响GPS精密测量的各个关键环节,着重研究了不同海潮负荷模型位移改正对GPS坐标精密定位的修正效果,建立了海潮负荷位移和天顶对流层延迟(ZTD)估计精度的变化特征关系,深入分析了未模型化的海潮负荷位移传播到GPS高程时间序列的混叠信号的周期变化特征。主要研究内容和成果如下： (1)系统研究了海洋潮汐和海潮负荷的理论基础,介绍了海洋潮汐产生的引潮位理论以及海洋潮汐的调和展开,给出了海洋潮汐和海潮负荷分析方法的详细表达式。 (2)系统研究了非差精密单点定位所涉及的基本理论,包括各种GPS时间系统及相互转化关系、各种GPS坐标系统及相互转化关系、基本观测方程和参数估计模型,针对数据处理过程中的误差项,着重分析了非差精密单点定位主要误差源和改正模型及方法。 (3)利用全球海潮模型FES2004的M2分潮波深入研究了我国海域的海潮空间特征分布,得出我国海域的M2分潮振幅主要分布为：较小振幅的南海区域,较大振幅的渤海、黄海和东海区域以及大陆近海岸的异常区域。在此研究基础上,给出了我国陆海全区域的海潮负荷位移三维坐标分量,海潮负荷的垂向位移分量为水平位移分量的3～4倍,同时在沿海陆地和近海海洋区域海潮位移变化较大。通过7种全球海潮模型分析了不同海潮负荷位移在我国不同区域范围内的影响差异,结果显示近海区域的不同海潮负荷位移的均方根误差较大,间接证明了全球海潮模型在我国近海区域精度具有较低的精度。 (4)针对我国及周边地区的13个IGS站,分别采用全球海潮模型和经近海海潮模型修正的全球海潮模型计算及分析了各测站的海潮负荷位移,并利用GPS实测数据研究了海潮负荷对单天解和短时段周期解的精度影响。实验结果表明局部近海海潮模型和全球海潮模型相应区域的精度相当,计算的海潮负荷位移未引起明显的差异。对于GPS单天解精密定位结果,从整体上各海潮负荷位移对测站坐标没有影响,但是在局部沿海地区测站的垂向坐标存在差异；对于GPS短周期精密定位,海潮负荷位移改正对我国沿海地区测站的精度能够提高2.5mm。 (5)深入分析了利用映射函数和水平梯度模型进行GPS天顶对流层延迟估计的精度,结果显示选用GMF映射函数会比NMF映射函数从整体上提高了ZTD估计精度。在低高度角和气象变化剧烈条件下,施加水平梯度改正也能提高ZTD估计精度。研究了ZTD与海潮负荷位移的关系,通过解算结果确定了在我国及周边地区的IGS站的海潮负荷位移垂向分量与ZTD变化具有显著的线性对应关系,同时二者的比例因子在2-5范围内变化。为了满足GPS气象学应用PWV值优于1mm的精度要求,特别是在沿海地区必须要顾及海潮负荷效应的作用对ZTD估计偏差的影响。 (6)系统研究了GPS高程时间序列的长周期混叠信号传播机制,确定了未建模的海潮负荷位移造成我国及周边地区8个测站的GPS高程时间序列长周期混叠信号周期和振幅分布特征,发现混叠信号主要集中于约14天、半年和周年周期,未建模的海潮负荷垂向位移引起GPS高程时间序列的混叠信号振幅能达到海潮负荷高程分量振幅的12%,而未建模的海潮负荷水平位移引起GPS高程时间序列的混叠信号振幅最大达到海潮负荷水平分量振幅的100%,同时基于未建模海潮负荷三维分量相对于未建模海潮负荷高程分量的GPS高程时间序列的频谱振幅和周期发生了明显变化,分析表明即使水平负荷位移量值很小,但是对于GPS高程时间序列混叠周期信号频谱特征解释具有不可忽视的作用。提出了通过GPS高程时间序列的频谱分析,利用特定频率的振幅峰值评估不同海潮模型的相对精度特征,为海潮负荷模型定量分析提供了简明的评估手段。
[Abstract]:The rapid development and extensive application of modern spatial positioning technology, represented by GPS (Global Positioning system), have accumulated a large amount of precious original observation data in the past 20 years, and have opened up a broad prospect for Geodesy and geophysics research fields. The results of high precision and high reliability GPS data processing are Geosciences. On the basis of the research, the correction of sea tide load displacement has been widely agreed to improve the GPS estimation precision, and it also provides an effective way for removing the effect of sea tide load effect in the GPS coordinate time series study. At the same time, the accuracy and adaptability of the tidal load model can be tested by the GPS coordinate time series analysis. Therefore, the precision measurement of the sea tide load model can be obtained by the GPS precision measurement. The study of ocean tide loading effect has important theoretical significance and reference value for obtaining accurate geometric and physical information in Geodesy and geophysics research.
This paper systematically expounds the current development status and trend of sea tide load effect in GPS precision measurement both at home and abroad, analyzes the key links of the sea tide load affecting the precision measurement of GPS, and focuses on the correction effect of the displacement correction of different tidal load models on the precision positioning of the GPS coordinates, and establishes the tidal load displacement and the zenith troposphere. The variation characteristics of the delay (ZTD) estimation precision are analyzed, and the periodic variation characteristics of the unmodeled sea tide load displacement propagating to the GPS elevation time series are analyzed. The main research contents and results are as follows:
(1) the theoretical basis of ocean tides and tidal loads is systematically studied. The tidal potential theory of ocean tides and the harmonic expansion of ocean tides are introduced. The detailed expressions of the analysis methods of ocean tides and tidal loads are given.
(2) the basic theory of non differential precision single point positioning is systematically studied, including various GPS time systems and mutual transformation relations, various GPS coordinate systems and mutual transformation relations, basic observation equations and parameter estimation models. In view of the error items in the process of data processing, the main error sources and changes of the non differential precision single point positioning are analyzed. Positive model and method.
(3) using the M2 tidal wave of the global sea tide model FES2004 to study the spatial characteristics of the sea tide in the sea area of China, it is concluded that the amplitude of the M2 tide is mainly distributed in the smaller amplitude of the South China Sea region, the larger amplitude of Bohai, the the Yellow Sea and the East China Sea region and the anomalous region of the Continental Coast. The three-dimensional coordinate component of the tidal load displacement in the whole region of the land and sea, the vertical displacement component of the sea tide load is 3~4 times the horizontal displacement component, and the tidal displacement of the coastal land and the coastal sea area changes greatly. The difference of the influence of the different tidal load position shift in different regions of China is analyzed by the 7 kinds of global tidal models. The results show that the root mean square error of the sea tide load displacement in the coastal area is large, which indirectly proves that the global sea tide model has a lower precision in the coastal area of China.
(4) according to the 13 IGS stations in China and the surrounding areas, the global tidal model and the global tidal model modified by the coastal sea tide model are used to calculate and analyze the tidal load displacement of each station, and the effect of the tidal load on the accuracy of the single day solution and the short-time Duan Zhou phase solution is studied by using the measured data of the GPS. The experimental results show that the local coastal waters are near the sea. The accuracy of the sea tide model and the corresponding region of the global sea tide model is equal, and the calculated sea tide load displacement does not cause significant difference. For the precision positioning results of GPS single day solution, the overall sea tide load displacement has no influence on the station coordinates, but the vertical coordinates of the stations in the local coastal areas are different, and for the short period precision of the GPS. Positioning and tidal load displacement correction can improve the accuracy of stations in China's coastal areas by 2.5mm.
(5) the accuracy of the GPS zenith tropospheric delay estimation using the mapping function and the horizontal gradient model is deeply analyzed. The results show that the GMF mapping function will improve the accuracy of the ZTD estimation from the NMF mapping function as a whole. The application of the horizontal gradient correction can also improve the ZTD estimation accuracy under the low altitude angle and the severe weather change. The relationship between the ZTD and the load displacement of the sea tide is obtained. Through the calculation, the linear corresponding relation between the vertical component of the tidal load displacement and the change of the ZTD in the IGS station in China and its surrounding area is determined. At the same time, the proportion factor of the two is changed within the range of 2-5. In order to meet the precision requirements of the application of the PWV value to the GPS meteorology, the PWV value is superior to the 1mm, especially in the application. Coastal area must take into account the effect of ocean tide loading effect on ZTD estimation bias.
(6) the long period aliasing signal propagation mechanism of the GPS height time series is systematically studied, and the period and amplitude distribution characteristics of the long period aliasing signal of the GPS elevation time series in China and the surrounding area are determined by the unmodeled sea tide load displacement. It is found that the aliasing signal is mainly concentrated on about 14 days, half a year and the annual cycle, and it is not modeled. The vertical displacement of the sea tide load causes the amplitude of the mixed signal of the GPS elevation time series to reach 12% of the amplitude of the tidal load elevation, while the unmodeled sea tide load horizontal displacement causes the maximum amplitude of the GPS elevation time series to reach 100% of the sea tide load horizontal component amplitude, and it is based on the unmodeled tidal load three-dimensional load. The spectral amplitude and cycle of the GPS elevation time series with respect to the unmodeled tidal load height components have changed obviously. The analysis shows that even if the horizontal load displacement value is very small, it has an unnegligible effect on the spectrum characteristic interpretation of the GPS elevation time series mixed cycle signal. It is proposed through the GPS elevation time sequence. The spectrum analysis of the column is used to evaluate the relative accuracy characteristics of different sea tide models by using the peak amplitude of the specific frequency, which provides a concise evaluation method for the quantitative analysis of sea tide load model.
【学位授予单位】：武汉大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P228.4;P731.2

【参考文献】