浅谈1∶10000基础测绘任务外业调绘的质量控制方法

结合生产实践,介绍了一种通过将最新的卫星遥感正射影像资料与上一轮数字线划图（DLG）数据进行套合的技术路线。利用这种方法能够对1∶10 000基础测绘地形图进行全要素的更新。本文还列举了外业调绘工序容易出现的一系列质量问题,分析了问题出现的原因,阐述了如何在生产过程中加强质量控制措施来提高产品的质量。     

空间坐标系变换的函数梯度描述方法

为了将空间坐标系变换由静态的、不随时间发生变换的情况推广到动态的、随时间发生变换以及任意角度发生变换的情况,基于单位四元数构造的旋转矩阵和罗德里格矩阵的完全等价性,揭示出空间坐标系（空间直角坐标系）变换与函数梯度的数学关系,推导出由函数梯度表示的空间坐标系变换的数学公式,在理论上说明了用函数梯度描述空间坐标系变换的方法。研究表明：在数学意义上,空间坐标系变换的本质是"场",可以用"场"的概念统一以任意角度发生旋转变换的空间坐标系变换特例。为进一步研究空间坐标系随时间发生连续变换的情况或以新的思路为运动载体定姿奠定了理论基础。     

Accuracy analysis for SST gravity field model in China

Taking China as the region for test the potential of the new satellite gravity technique, satelliteto-satellite tracking for improving the accuracy of regional gravity field model is studied. With WDM94 as reference, the gravity anomaly residuals of three models, the latest two GRACE global gravity field model (EIGEN_GRACE02S, GGM02S) and EGM96, are computed and compared. The causes for the differences among the residuals of the three models are discussed. The comparison between the residuals shows that in the selected region, EIGEN_GRACE02S or GGM02S is better than EGM96 in lower degree part (less than 110 degree). Additionally, through the analysis of the model gravity anomaly residuals, it is found that some systematic errors with periodical properties exist in the higher degree part of EIGEN and GGM models, the results can also be taken as references in the validation of the SST gravity data.     

多个超高阶重力场模型精度分析

分析了国际和国内公布的EGM2008、GECO、Eigen6c4、UGM2005、DQM2000d和DQM2006等超高阶重力场模型的内符合精度;利用中国境内的实测GPS/水准数据对各类模型进行了外符合精度检验;结合不同的方法对系统差进行了处理;最后基于试验区数据讨论了不同模型之间频谱组合方法对高程异常计算结果的改善情况。实验表明,Eigen-6C4模型具有更高的内符合精度,国内公布的UGM2005和DQM2006两种模型精度相当;本文提出的十参数法相比于传统四参数方法精度获得了4.6%~22.20%的提升;GECO模型和Eigen-6C4模型在实验区内外符合精度较好;不同模型之间的频谱组合可以在一定程度上提高试验区内模型确定高程异常的精度。     

随机Dirichlet问题解的调和展开

针对重力学随机Dirichlet问题,通过适当地对边界检验函数的分解,并在随机边界样本空间中提取确定性部分的对偶基,本文将随机Dirichlet问题的一般解展开为一随机系数的调和级数形式。     

A data-driven approach to local gravity field modelling using spherical radial basis functions

We propose a methodology for local gravity field modelling from gravity data using spherical radial basis functions. The methodology comprises two steps: in step 1, gravity data (gravity anomalies and/or gravity disturbances) are used to estimate the disturbing potential using least-squares techniques. The latter is represented as a linear combination of spherical radial basis functions (SRBFs). A data-adaptive strategy is used to select the optimal number, location, and depths of the SRBFs using generalized cross validation. Variance component estimation is used to determine the optimal regularization parameter and to properly weight the different data sets. In the second step, the gravimetric height anomalies are combined with observed differences between global positioning system (GPS) ellipsoidal heights and normal heights. The data combination is written as the solution of a Cauchy boundary-value problem for the Laplace equation. This allows removal of the non-uniqueness of the problem of local gravity field modelling from terrestrial gravity data. At the same time, existing systematic distortions in the gravimetric and geometric height anomalies are also absorbed into the combination. The approach is used to compute a height reference surface for the Netherlands. The solution is compared with NLGEO2004, the official Dutch height reference surface, which has been computed using the same data but a Stokes-based approach with kernel modification and a geometric six-parameter “corrector surface” to fit the gravimetric solution to the GPS-levelling points. A direct comparison of both height reference surfaces shows an RMS difference of 0.6 cm; the maximum difference is 2.1 cm. A test at independent GPS-levelling control points, confirms that our solution is in no way inferior to NLGEO2004.     

基于Oracle Spatial的多元重力场信息数据库的设计与应用

随着地球重力场信息多元化的发展及其应用领域越来越广,科学高效的管理和应用重力场信息数据就显得尤为重要。文中介绍了基于Oracle Spatial技术设计与构建的重力场信息数据库的结构框架,分析了存储数据信息的种类、属性及特点,研究了数据的存储方式。在多元化重力场数据与基础地图数据统一管理的基础上,初步实现了多元化重力场信息的存储、查询、计算、绘图及显示等功能。     

地壳运动速度场插值方法研究

分析了构建速度场的统计模型和函数模型法,提出利用两种模型逼近原始观测速度的综合逼近法,以减少剩余误差。计算和比较了各种方法,结果显示,综合法优于单独利用统计模型和函数模型法。     

Modeling errors in upward continuation for INS gravity compensation

Accurate upward continuation of gravity anomalies supports future precision, free-inertial navigation systems, since the latter cannot by themselves sense the gravitational field and thus require appropriate gravity compensation. This compensation is in the form of horizontal gravity components. An analysis of the model errors in upward continuation using derivatives of the standard Pizzetti integral solution (spherical approximation) shows that discretization of the data and truncation of the integral are the major sources of error in the predicted horizontal components of the gravity disturbance. The irregular shape of the data boundary, even the relatively rough topography of a simulated mountainous region, has only secondary effect, except when the data resolution is very high (small discretization error). Other errors due to spherical approximation are even less important. The analysis excluded all measurement errors in the gravity anomaly data in order to quantify just the model errors. Based on a consistent gravity field/topographic surface simulation, upward continuation errors in the derivatives of the Pizzetti integral to mean altitudes of about 3,000 and 1,500 m above the mean surface ranged from less than 1 mGal (standard deviation) to less than 2 mGal (standard deviation), respectively, in the case of 2 arcmin data resolution. Least-squares collocation performs better than this, but may require significantly greater computational resources.     

UKF在基于地磁场的自主导航中的应用

本文研究了基于地磁场的自王导航,建立了以卫星轨道动力学方程为基础的系统状态方程,并详细推导了以地磁场矢量为观测量时的观测方程;为了解决系统的非线性问题把常用来解决非线性问题的UKF引入到基于地磁场的自主导航系统中;最后,用Matlab对基于地磁场的自主导航系统进行了仿真,仿真结果表明UKF有很好的收敛性和稳定性.