基于中心点平移的坐标转换精度分析

提出了基于局部地区或图幅的中心点平移进行坐标转换的方法,并通过实例分析,证明该方法不仅能够满足坐标转换精度要求,而且简单易行,适合地勘单位批量进行地质工程测量成果的坐标转换。     

基于网络的航天靶场大地测量管理系统研究

针对航天靶场大地测量各环节数据链脱节、成果数据和资料档案管理基于人工模式这一现状,提出构建基于网络的航天靶场大地测量成果数据与资料档案关联存取、数据生产与服务结合的一体化管理系统,阐述了系统研制的主要目标和内容。结合实际作业流程,详细设计了成果数据和资料档案管理功能,论述了系统开发的关键技术,解决了各类数据的在线共享,实现了航天靶场大地测量的信息化管理。     

From Discrete Gravity Survey Data to a High-resolution Gravity Field Representation in the Nordic-Baltic Region

The deduction of a regularly spaced gravity anomaly grid from scattered survey data is studied, addressing mainly two aspects: reduction of gravity to anomalies and subsequent interpolation by various methods. The problem is illustrated in a heterogeneous study area and contrasting test areas including mountains, low terrains, and a marine area. Provided with realistic error estimates, Least Squares Collocation interpolation of Residual Terrain Model anomalies yields the highest quality gravity grid. In most cases, the Bouguer reduction and other interpolation methods tested are equally viable. However, spline-based interpolation should be avoided in marine areas with trackwise survey data.     

Solutions of the linearized geodetic boundary value problem for an ellipsoidal boundary to order e 3

The geodetic boundary value problem (GBVP) was originally formulated for the topographic surface of the Earth. It degenerates to an ellipsoidal problem, for example when topographic and downward continuation reductions have been applied. Although these ellipsoidal GBVPs possess a simpler structure than the original ones, they cannot be solved analytically, since the boundary condition still contains disturbing terms due to anisotropy, ellipticity and centrifugal components in the reference potential. Solutions of the so-called scalar-free version of the GBVP, upon which most recent practical calculations of geoidal and quasigeoidal heights are based, are considered. Starting at the linearized boundary condition and presupposing a normal field of Somigliana–Pizzetti type, the boundary condition described in spherical coordinates is expanded into a series with respect to the flattening f of the Earth. This series is truncated after the linear terms in f, and first-order solutions of the corresponding GBVP are developed in closed form on the basis of spherical integral formulae, modified by suitable reduction terms. Three alternative representations of the solution are discussed, implying corrections by adding a first-order non-spherical term to the solution, by reducing the boundary data, or by modifying the integration kernel. A numerically efficient procedure for the evaluation of ellipsoidal effects, in the case of the linearized scalar-free version of the GBVP, involving first-order ellipsoidal terms in the boundary condition, is derived, utilizing geopotential models such as EGM96.     

大地测量反演线弹性构造应力场

本文基于地表大地测量位移观测值，提出用大地测量监测资料反演线弹性构造应力场方法。讨论了大地测量监测点分布式、观测随机误差以及岩体介质参数对边界力系数反演值的影响，为实际应用大地测量资料反演线弹性构造应力场提供了参考依据。     

The solution of the general geodetic boundary value problem by least squares

 A general scheme is given for the solution in a least-squares sense of the geodetic boundary value problem in a spherical, constant-radius approximation, both uniquely and overdetermined, for a large class of observations. The only conditions are that the relation of the observations to the disturbing potential is such that a diagonalization in the spectrum can be found and that the error-covariance function of the observations is isotropic and homogeneous. Most types of observations used in physical geodesy can be adjusted to fit into this approach. Examples are gravity anomalies, deflections of the vertical and the second derivatives of the gravity potential. Received: 3 November 1999 / Accepted: 25 September 2000     

Iterative vector methods for computing geodetic latitude and height from rectangular coordinates

 Two iterative vector methods for computing geodetic coordinates (φ, h) from rectangular coordinates (x, y, z) are presented. The methods are conceptually simple, work without modification at any latitude and are easy to program. Geodetic latitude and height can be calculated to acceptable precision in one iteration over the height range from −10⁶ to +10⁹ m. Received: 13 December 2000 / Accepted: 13 July 2001     

Decomposition of deformation primitives of horizontal geodetic networks: application to Taiwan’s GPS network

The contribution to each component of the deformation vector due to a marginally undetected blunder in an observation is split into two parts, and so are the deformation measures at a point. The first part, called the local component (or self component), signifies the contribution due to the redundancy-related multiplier belonging to the observation itself, while the second part, called the complementary component, shows the contribution due to the non-redundancy-related multipliers belonging to the observation. A larger redundancy results in a smaller local component for each component of the deformation vector. However, robustness due to an observation at a point is correlated with redundancy to a significant extent. The first-order global positioning system (GPS)-geodetic network of Taiwan was examined for its robustness. The experiments seem to indicate that: (1) large deformations tend to be found at points where the group redundancies are small; (2) the local components monopolize deformation measures at the perimeter stations of the network where very small redundancy numbers are found; (3) the largest deformation at a point may be due to an observation not directly tied to the point of interest; and (4) except for local twisting, deformation measures and mean positional precisions at individual points are highly correlated.Acknowledgement The authors thank Drs. A.A. Simkooei, M. Schmidt, and M.R. Craymer greatly for their constructive comments and suggestions, which improved the quality of the paper. This research was supported by National Science Council of Taiwan (contract number NSC-91-2211- E-002-085).     

An alternative algebraic algorithm to transform Cartesian to geodetic coordinates

The algorithm to transform from 3D Cartesian to geodetic coordinates is obtained by solving the equation of the Lagrange parameter. Numerical experiments show that geodetic height can be recovered to 0.5 mm precision over the range from −6×10⁶ to 10¹⁰ m. Electronic Supplementary Material: Supplementary material is available in the online version of this article at     

唐山及大同－阳高地震大地形变与重力前兆综合研究

本大概还了近年来利用大地形变及重力复测资料研究唐山及大同－阳高地震的丰富成果，对这２次地震震前大地形变及重力前兆综合研究认为：震中区震前呈现闭锁状态；断层蠕滑及深部物质的运移，是震前的显著标志；地震成因的组合模式可以较好地解释唐山及大同一阳高地震的机制；跟踪监测形变场、重力场及断层活动时空演化特性，是利用大地形变及重力测量手段进行地震预测的基本出发点。