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1.
介绍了日本曾采用了百余年的大地基准TD1918,阐述了它不能适应当前日本的经济、社会和军事发展的需求,日本于2002年开始采用新的地心三维大地基准JGD2000.概要介绍了JGD2000大地系统的定义及其框架,最后给出了这两个新老大地基准的转换. 相似文献
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Accurate geocentric three dimensional positioning is of great importance for various geodetic and oceanographic applications.
While relative positioning accuracy of a few centimeters has become a reality using Very Long Baseline Interferometry (VLBI), the uncertainty in the offset of the adopted coordinate system origin from the geocenter is still believed to be of the
order of one meter. Satellite Laser Ranging (SLR) is capable of determining this offset to better than10 cm, though, because of the limited number of satellites, this requires a long arc of data. The Global Positioning System (GPS) measurements provide a powerful alternative for an accurate determination of this origin offset in relatively short period
of time. Two strategies are discussed, the first utilizes the precise relative positions predetermined byVLBI, where as the second establishes a reference frame by holding only one of the tracking sites longitude fixed. Covariance
analysis studies indicate that geocentric positioning to an accuracy of a few centimeters can be achieved with just one day
of preciseGPS pseudorange and carrier phase data. 相似文献
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我国大地坐标系的换代问题 总被引:22,自引:3,他引:22
魏子卿 《武汉大学学报(信息科学版)》2003,28(2):138-143,148
首先指出了我国现有大地坐标系在先进性和实用性方面存在的问题,提出了我们面临的选择与采用地心坐标系的建议,然后就地心坐标系的定义和实现、参考椭球常数、正常重力公式等问题提出了初步意见,并就坐标系改变对旧地形图的影响问题进行了研究。我国大地坐标系应由局部坐标系更新为地心坐标系。我国大地坐标系的定义应与IERS(国际地球自转服务)协议相一致,采用国际常用的参考椭球和正常重力公式。本文提出的参考椭球和正常重力公式符合这些原则,提出的地形图坐标系变化改正方案应是基本可行的。 相似文献
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V. S. Schwarze 《Journal of Geodesy》1999,73(11):594-602
The reformulation of geodetic measurement processes within the framework of general relativity is discussed. The metric tensor
plays an important role in general relativity and has to be represented with respect to a set of appropriate charts. Almost
every quantity of interest in geodetic or geophysical applications refers to a geocentric, Earth-fixed coordinate system (chart),
therefore they are of great importance in geodesy and geophysics. The space–time metric with respect to an Earth-fixed chart
is derived at first post-Newtonian order. The field equations determining the terrestrial gravitational field are derived
and its explicit representation is outlined. The impact of the results on the modelling of geodetic measurement processes
including space–time positioning scenarios as well as the high-precision gravitational field estimation is outlined.
Received: 7 January 1998 / Accepted: 17 August 1999 相似文献
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国家坐标系的独立坐标系建立后,原国家坐标系的控制点不能直接应用于独立坐标系中,需要确定并计算得出独立坐标系的基准。独立坐标系的基准确定直接关系到独立坐标系的精度及其与国家坐标系间的转换。随着测绘技术的发展,一些原有的传统基准确定方法已不能满足高精度地心坐标系的要求,因此本文对地心坐标系的独立坐标系的基准确定方法进行了探讨。 相似文献
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Robust estimation of geodetic datum transformation 总被引:18,自引:1,他引:17
Y. Yang 《Journal of Geodesy》1999,73(5):268-274
The robust estimation of geodetic datum transformation is discussed. The basic principle of robust estimation is introduced.
The error influence functions of the robust estimators, together with those of least-squares estimators, are given. Particular
attention is given to the robust initial estimates of the transformation parameters, which should have a high breakdown point
in order to provide reliable residuals for the following estimation. The median method is applied to solve for robust initial
estimates of transformation parameters since it has the highest breakdown point. A smooth weight function is then used to
improve the efficiency of the parameter estimates in successive iterative computations. A numerical example is given on a
datum transformation between a global positioning system network and the corresponding geodetic network in China. The results
show that when the coordinates are contaminated by outliers, the proposed method can still give reasonable results.
Received: 25 September 1997 / Accepted: 1 March 1999 相似文献
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株洲市基于CGCS2000的城市控制网升级改造,获取了株洲市2000国家大地坐标系的大地基准和原有城市控制点及升级改造后控制点的2000国家大地坐标,并通过了检测验收;改造升级了的株洲城市控制网,更新了株洲市控制网的1954坐标,建立了与2000国家大地坐标系、1980坐标的转换关系,实现了基于CZTCORS网络RTK技术的似大地水准面成果的应用. 相似文献
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借助具有强大符号运算功能的计算机代数系统Mathematica,推导了地图投影学中等距离纬度、等角纬度、等面积纬度与地心纬度之间的正反解直接展开式,并将式中的系数统一表示成关于椭圆偏心率e和椭球第三扁率n的幂级数形式。与以往反解方法不同的是,采用符号迭代法进行以地心纬度为变量的等距离纬度、等角纬度、等面积纬度的反解,并使用最大差异值作为衡量精度的标准。算例分析表明,以地心纬度为变量的常用纬度展开式在结构和形式上与以大地纬度为变量的辅助纬度保持一致,基于第三扁率n的幂级数表达式具有更紧凑的形式和更好的收敛性,其直接展开式的精度分别优于(1×10-8)″和(1×10-10)″,可以满足大地测量和地图投影精密计算的需要。 相似文献
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Christopher Kotsakis 《Journal of Geodesy》2008,82(4-5):261-260
Transforming height information that refers to an ellipsoidal Earth reference model, such as the geometric heights determined
from GPS measurements or the geoid undulations obtained by a gravimetric geoid solution, from one geodetic reference frame
(GRF) to another is an important task whose proper implementation is crucial for many geodetic, surveying and mapping applications.
This paper presents the required methodology to deal with the above problem when we are given the Helmert transformation parameters
that link the underlying Cartesian coordinate systems to which an Earth reference ellipsoid is attached. The main emphasis
is on the effect of GRF spatial scale differences in coordinate transformations involving reference ellipsoids, for the particular
case of heights. Since every three-dimensional Cartesian coordinate system ‘gauges’ an attached ellipsoid according to its
own accessible scale, there will exist a supplementary contribution from the scale variation between the involved GRFs on
the relative size of their attached reference ellipsoids. Neglecting such a scale-induced indirect effect corrupts the values
for the curvilinear geodetic coordinates obtained from a similarity transformation model, and meter-level apparent offsets
can be introduced in the transformed heights. The paper explains the above issues in detail and presents the necessary mathematical
framework for their treatment.
An erratum to this article can be found at 相似文献
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韩国和马来西亚建立本国三维地心大地坐标系统的进展 总被引:1,自引:0,他引:1
介绍了韩国大地坐标系统的沿革 ,阐述了近年来韩国建立本国三维地心坐标系的工作和进展。为了对比韩国 ,简约介绍了马来西亚等国在这方面的新进展 相似文献
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Height datum definition,height datum connection and the role of the geodetic boundary value problem 总被引:3,自引:3,他引:3
Vertical datum definition is identical with the choice of a potential (or height) value for the fundamental bench mark. Also
the connection of two adjacent vertical datums poses no principal problem as long as the potential (or height) value of two
bench marks of the two systems is known and they can be connected by levelling. Only the unification of large vertical datums
and the connection of vertical datums separated by an ocean remains difficult.
Two vertical datums can be connected indirectly by means of a combination of precise geocentric positions of two points, as
derived by space techniques, their potential (or height) value in the respective height datum and their geoid height difference.
The latter requires the solution of the linear geodetic boundary value problem under the assumption that potential and gravity
anomalies refer to a variety of height datums. The unknown off-sets between the various datums appear in the solution inside
and outside the Stokes integral and can be estimated in a least squares adjustment, if geocentric positions, levelled heights
and adequate gravity material are available for all datum zones. The problem can in principle also be solved involving only
two datums, in case a precise global gravity field becomes available purely from satellite methods. 相似文献
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2000国家大地坐标系是我国自主建立、适应现代空间技术发展趋势的地心坐标系。辽宁省2000国家大地坐标框架的建立,可以实现与国家现代测绘基准体系的无缝对接,对测绘事业的发展和基于全球导航卫星系统(GNSS)技术的高精度位置服务产生重大影响和作用。本文主要讲述了辽宁省2000国家大地坐标框架建设取得的进展,介绍了坐标框架建立过程中的关键技术应用以及对辽宁省测绘基准体系建设和测绘科技发展的推动作用。 相似文献
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国家测绘局(国测国字〔2008〕24号)规定,自2008年7月1日起,启用2000国家大地坐标系,并明确其与现行国家大地坐标系转换、衔接的过渡期为8~10年。本文以惠阳建立测绘基准转换关系统一测绘基准为例,详细阐述此项工作的操作、依据、措施,评价新系统的质量精度等,供同业者参考。 相似文献
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A. M. C. Srivastava 《Journal of Geodesy》1984,58(4):510-517
The astrogeodetic—gravimetric method based on the principle of least—squares solution has been used to determine the geocentric
Indian geodetic datum making use of the available nongeocentric astrogeodetic data and the gravimetric geocentric geoidal
heights in the form of smoothened values. Everett's method of interpolation has been used to obtain the smoothened geoidal
heights at the astrogeodetic stations in India from the available generalized values at 1°×1° corners. The values of the geoidal
height and deflections of the vertical at the geodetic datum Kalianpur H.S. so obtained have the negligible difference from
the values computed earlier by the same method using directly computed gravimetric geoidal heights at the astrogeodetic stations,
indicating that the use of the interpolated values in the astrogeodetic—gravimetric method employed would be an economical
approach of absolute orientation of a nongeocentric system if the gravimetric geoidal heights are available at 1°×1° corners
in the area of interest. 相似文献
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一种大地坐标变换的快速算法 总被引:3,自引:0,他引:3
大地纬度的解算是从地心直角坐标到大地坐标变换的关键 ,传统上多采用迭代法 ,效率较低 ,难以满足实时性较高的应用。本文给出了一种非迭代的、采用有理多项式逼近的方法来计算大地纬度 ,并且通过与 Heikkinen、改进 Bowring、Ozone三种算法的比较证明这是一种速度极快的算法 ,而且在 5 0公里以下的范围内 ,采用这种算法的平均误差不超过 1毫米 相似文献
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大地纬度的解算是从地心直角坐标到大地坐标变换的关键 ,传统上多采用迭代法 ,效率较低 ,难以满足实时性较高的应用。本文给出了一种非迭代的、采用有理多项式逼近的方法来计算大地纬度 ,并且通过与 Heikkinen、改进 Bowring、Ozone三种算法的比较证明这是一种速度极快的算法 ,而且在 5 0公里以下的范围内 ,采用这种算法的平均误差不超过 1毫米 相似文献