选权拟合的粗差参数化平差模型

由于数据探测法、多维粗差同时定位与定值法、拟准检定法以及部分最小二乘法不能同时解算待估参数和粗差,提出了基于选权拟合的粗差参数化平差模型。首先推导了选权拟合的等价模型;在此基础上提出了参数化粗差的平差模型。由于粗差参数化之后观测系统呈现出不适定性,因此,对非粗差部分采取平方和最小的约束,实际上是构造虚拟观测方程。但是,由于事先并不知道粗差的位置,提出了通过搜索来构造虚拟观测方程系数矩阵的方法。算例表明,这种方法用于GPS单点定位可以有效地消除粗差观测的影响。     

绝对值极小平差法的研究

在实际观测误差中,有时存在少量的粗差.此时,最小二乘法的平差结果往往会受到严重歪曲和影响,而绝对值极小平差法同最小二乘法相比较,有较好的抗粗差能力.本文主要介绍了绝对值极小平差法所采用的数学模型、解的不唯一性以及该方法在抗粗差能力方面同最小二乘法的比较结果.     

历元间差分定位模型的粗差探测法探测周跳

假设前一历元的测站点为已知点,当前历元的测站点为未知点,当前历元和前一历元相同卫星的相位观测值取差作为观测值,观测值与当前历元点位坐标的函数关系式称为历元间差分定位模型.本文以历元间差分定位模型构造误差方程,进行最小二乘平差,提出应用Baarda数据探测法对差分观测值进行粗差探测,可准确确定观测值中的周跳.实际算例验证...     

用抗差估计法实施全国天文大地网与空间网联合平差

全国天文大地网与空间网联合平差二期工程参加平差的观测量达到42万条,观测年代跨度40多年,测量仪器、测量技术规范和测量方法差别很大。虽然平差之前对观测数据进行了粗差探测与剔除,还是无法确保观测数据完全准确,有必要利用抗差估计方法实施联合平差解算,提高联合平差结果的精度。本文详细地讨论了抗差估计在联合平差中的应用,对Huber和IGGUI方案进行分析比较,选择合适的权函数,有效控制观测异常对平差结果的影响。     

抗差岭型组合主成分估计及误差影响

本文从有偏估计类中的岭型组合主成分估计出发 ,结合抗差估计理论 ,利用抗差M估计模型 ,提出了一种新的抗差有偏估计法———抗差岭型组合主成分估计。推导了平差参数的抗差岭型组合主成分估计解 ,以及平差参数的验后精度和误差影响函数。计算结果表明 ,抗差岭型组合主成分估计不但能克服法方程系数阵病态性的影响 ,而且能有效地抵制观测值中精差的异常干扰 ,使参数的解更为准确可靠     

基于验后方差原理的选择权迭代法定位粗差

当观测数据中存在粗差时,使用经典的最小二乘算法往往不能得到高精度的参数解,此时需要使用具有抗差估计的算法。基于验后方差的选权迭代法,克服了单位权方差未知或者权函数靠经验选取的情况,利用验后方差检验求出方差异常大(即含粗差)的观测值,然后通过不断的迭代,使含粗差的权逐渐趋于一个较小的数,最终实现粗差的探测和改正。结合工程实例,分别比较了不含粗差和含粗差的情况下,利用经典最小二乘法与本文所提的基于验后方差原理的选权迭代法进行平差,结果表明,二者的平差结果相差在1mm以内,解算精度相当。     

Helmert方差分量估计的粗差检验与抗差解

当观测值中含有粗差时，检验表明Helmert方差分量估计结果同样含有粗差，且粗差还可能会发生转移，为有效地抵制粗差和随机模型差的互相影响，指出了发生这一转移的原因，介绍了基于双因子等价权的抗差估计，并针对相关Helmert方差分量估计抗差解求解过程中容易出现的法矩阵0值溢出问题，提出了改进方法。     

基于抗差EKF的GNSS/INS紧组合算法研究

提出了GNSS/INS紧组合导航的抗差EKF算法,采用21状态GNSS/INS紧组合状态方程,根据多余观测分量及预测残差统计构造抗差等价增益矩阵,建立抗差EKF算法,通过迭代给出GNSS/INS组合导航的抗差解,并开发GNSS/INS紧组合导航模拟平台,通过对观测值加入单粗差、多粗差及缓慢增长三类误差,测试本文算法对不同粗差的抑制能力。分析表明,抗差EKF可以将三类粗差抑制在相应观测值的残差中,达到削弱其对状态参数估计的影响。本文算例证明,抗差EKF算法可将导航解的误差精度从dm级提高为cm级甚至mm级,导航精度及可靠性得到明显提高。     

动态平差概括模型及形变与粗差的定位定值方法

本文首先建立了包括常规动态平差模型和静态平差模型的动态平差概括函数模型,推导了该模型下的主要平差计算公式和精度评定公式,指出动态平差对静态分期平差有良好的概括性,并讨论了动态平差模型下形变与粗差的统计区分检验公式与方法。其次探讨了多维粗差定位定值的基础,指出粗差分析的基本依据是反映观测值真误差之间线性函数关系的条件方程,而不是最小二乘平差后的残差向量V。提出了多维粗差的直接定位与定值法（LEGED法）和适合于各种最小二乘平差函数模型的多维粗差的统一定位与定值法（LEGU法）,指出LEGEU法的实质等价于LEGED法。算例表明,LEGED法和LEGEU法不仅能准确确定多个粗差的位置,而且能直接计算粗差的大小,且粗差估值与粗差真值之差属于随机误差的量级。然后探讨了粗差的定位定值特性,指出只有当粗差个数是与粗差的最小图相关数S满足k≤s－2时,才能确定粗差的位置和大小,说明了图相关粗差的不可区分性不会因为数据处理方法的不同而有所改变,提出了顾及粗差定位定值特性的粗差定位定值方法。最后论述了形变分析的实质,提出了比较完整的一般形变分析模型下形变与粗差同时定位定值的新方法。     

条件平差模型两种粗差检验方法的等价性

针对测量数据处理中常用的条件平差模型,该文介绍了条件平差模型按残差进行粗差探测的方法和实施步骤,导出了条件平差模型按观测值偏差进行粗差探测的公式,证明了当观测误差独立时,这两种检验方法对于检验单个粗差的等价性。并通过算例证实了直接利用偏差估值构建的检验单个独立观测值的统计量与按残差构建的统计量完全相同。     

Book Reviews

Books reviewed:
K. B. Atkinson, Close Range Photogrammetry And Machine Vision
R. A. Earnshaw and D. Watson, Animation And Scientific Visualization—Tools And Applications
R. A. Earnshaw, M. A. Gigante and H. Jones, Virtual Reality Systems
S. Macdonald, Mapping The World
P. Fisher, Innovations in GIS 2
A. Gruen, O. Kuebler and P. Agouris, Automatic Extraction of Man-Made Objects From Aerial and Space Images
H. Campbell and I. Masser, GIS and Organisations
S. C. Guptill and J. L. Morrison, Elements of Spatial Data Quality
D. Shirvanian, European Space Directory, 1996
D. R. Green, D.Rix and C. Corbin, The Agi Source Book for Geographic Information Systems, 1996
K. C. Graf, Realistic Landscape Rendering Using Remote Sensing Images, Digital Terrain Models and 3D Objects     

Book Reviews

Books reviewed:
M. Petrou and P. Bosdogianni, Image Processing, The Fundamentals
S. N. Lane, K. S. Richards and J. H. Chandler, Landform Monitoring, Modelling And Analysis
T. M. Lillesand and R. W. Kiefer, Remote Sensing And Image Interpretation
A. S. Câmara and J. Raper, Spatial Multimedia And Virtual Reality
M. N. Demers, Fundamentals Of Geographic Information Systems
J. L. Casanova, Remote Sensing In The 21st Century: Economic And Environmental Applications
G. McGrath and L. M. Sebert, Mapping A Northern Land: The Survey Of Canada
A. S. Milman, Mathematical Principles Of Remote Sensing: Making Inferences From Noisy Data
K. Kraus, Photogrammetrie Band 3: Topographische Informations-systeme
E. M. João, Causes And Consequences Of Map Generalisation
R. B. Parry and C. R. Perkins, World Mapping Today
P. M. Mather, Computer Processing Of Remotely Sensed Images: An Introduction
M. E. Schaepman, Calibration Of A Field Spectroradiometer
J. C. Iliffe, Datums And Map Projections For Remote Sensing, Gis And Surveying     

低空无人机交叉口悬停影像抖动纠正

低空无人机影像在交通规划、城市管理、应急监控等领域正逐渐体现出其独到的优势,而将影像快速、准确地纠正与配准则是其发挥功用的必要前提。以拍摄于道路交叉口上方的无人机悬停视频为研究对象,探讨对其实现影像抖动纠正配准的方法。视频中的连续影像包含大量的近似地物及移动地物,难以直接采用传统的空间域或频率域方法进行配准。由此,提出了一种基于横道线识别的影像配准方法,经由图斑提取、筛选分类、轴线拟合及影像配准等步骤,实现了影像任意帧间的配准。利用无人机悬停拍摄的交叉口视频进行了验证,结果表明,该方法稳健、有效。     

BOOK REVIEWS

Book review in this Article
THE UNITED KINGDOM FROM SPACE (2). By D. J. C arter and H. J. P. A rnold . Space Frontiers Ltd. Havant, Hampshire , 1977.
SURVEYS FOR DEVELOPMENT. Edited by J. J. N ossin . Elsevier Scientific Publishing Co. Amsterdam, Oxford, New York , 1977.
REMOTE SENSING OF THE TERRESTRIAL ENVIRONMENT. Edited by R. F. P eel , L. F. C urtis and E. C. B arrett . Butterworths, London , 1977.
MAPPING FOR FIELD SCIENTISTS. By W. R itchie , D. A. T ait , M. W ood and R. W right . David and Charles, Newton Abbot, Devon , 1977.
SURVEYING AND PHOTOGRAMMETRY. COMPUTATION FOR CIVIL ENGINEERS. By D. E. M urchison . Newnes–Butterworths, London , 1977.
RESOURCE SENSING FROM SPACE: PROSPECTS FOR DEVELOPING COUNTRIES. Report of the Ad Hoc Committee on Remote Sensing for Development. US National Academy of Sciences, Washington, D.C. , 1977.
MISSION TO EARTH: LANDSAT VIEWS THE WORLD. By N. M. S hort , P. D. L owman , S. C. F reden and W. A. F inch . National Aeronautics and Space Administration, Washington, D.C. , 1976.
REMOTE SENSING IN GEOMORPHOLOGY. By H. T h . V erstappen . Elsevier Scientific Publishing Company, Amsterdam, Oxford, New York , 1977.     

Measurement of soil water content using ground-penetrating radar: a review of current methods

Soil water content (SWC) is a crucial parameter in ecology, agriculture, hydrology, and engineering studies. Research on non-invasive monitoring of SWC has been a long-lasting topic in these fields. Ground penetrating radar (GPR), a non-destructive geophysical technique, has the advantages of high resolution, deep detection depth, and high efficiency in SWC measurements at medium scale. It has been successfully applied in field investigations. This paper summarizes the recent progress in developing GPR-based SWC measurement methods, including reflected wave, ground wave, surface reflection, borehole GPR, full waveform inversion, average envelope amplitude, and frequency shift methods. The principles, advantages, limitations, and applications of these methods are described in detail. A comprehensive technical framework, which comprises the seven methods, is proposed to understand their principles and applicability. Two key procedures, namely, data acquisition and data processing, are emphasized as crucial to method applications. The suitable methods that will satisfy diverse application demands and field conditions are recommended. Future development, potential applications, and advances in hardware and data processing techniques are also highlighted.     

Coastal landform mapping around the Gulf of Khambhat using Landsat TM data

Landsat TM data was utilised for coastal geomorphic mapping around the Gulf of Khambhat. Various landforms like shoreline, estuaries, mudflats, islands, mangroves, relict aluvium, cliffs, dunes, flood plains, paleochannel, paleomeanders, oxbow lake, etc. were delineated. The estuaries were divided into salt-wedge estuary, fully mixed estuary and partially mixed estuary based on amount of freshwater discharge and nature of tidal currents. The mudflats were classified into high tide flats, intertidal slopes and subtidal zones. These classes were further classified based on their composition. It was concluded that TM data has broughtout many new features and improved the classification of coastal landforms. The presence of coastal features like drowned river valleys, paleomudflats, relict alluvium, dunes, paleomeanders, oxbow lake and terraces clearly indicate the sea-level changes of the Quarternary period.     

International Society for Photogrammetry and Remote Sensing Symposia, 1994

I. J. Dowman, Systems For Data Processing, Analysis And Representation, p. 145
A. M. Morgado, Spatial Information From Digital Photogrammetry And Computer Vision, p. 147
P. R. T. Newby, Mapping And Geographic Information Systems, p. 148
D. A. Tait, Facing The Chance And The Challenge, p.154
P. J. Curran, Eco Rio '94, p.155     

利用WAVELAB开发小波应用程序的研究

论述了小波分析软件WAVELAB的系统构成，分析了该软件的开发环境，研究了利用该软件开发MATLAB小波应用程序的问题，并给出了以Lena图像实例的小波压缩编码程序及其运行结果。结果表明，利用WAVELAB开发小波应用软件是可行的。     

论空间数据挖掘和知识发现

随着现代科技和传感器的发展和应用，复杂多变的空间数据日益膨胀，远远超出人的解译能力，迫切需要数据挖掘和知识发现为其提供知识。本文研究了空间数据挖掘和知识发现的含义、可发现的空间的关联、特征、分类和聚类等知识，以及它与数据挖掘与知识发现、机器学习、地学数据分析、空间数据库、空间数据仓库、数字地球等相关学科的关系，概述了SDMKD的产生和发展，分析和展望了SDMKD的应用开发。     

BOOK REVIEWS

Book review in this Article
TERRAIN ANALYSIS AND CLASSIFICATION USING AERIAL PHOTOGRAPHS: a geomorphological approach. By R. A. and F. J. van Z uidam . International Institute for Aerial Survey and Earth Sciences (ITC), Enschede, Netherlands , 1978–9.
COMPLETE INDEX TO PHOTOGRAMMETRIC ENGINEERING AND REMOTE SENSING. Volumes I-XLV: 1934–1979. American Society of Photogrammetry, Falls Church, Virginia , 1980.
FUNDAMENTALS OF SURVEYING. By M. O. S chmidt and W. H. R ayner . Second Edition. Van Nostrand Company, New York , 1978.
REPORT OF SECOND EXPERT CONSULTATION ON A WORLD INDEX OF SPACE IMAGERY. Prepared by J. A. H oward and A. van D ijk . Food and Agriculture Organisation of the United Nations, Rome , 1980.
PROGRESS IN CONTEMPORARY CARTOGRAPHY, VOLUME I: THE COMPUTER IN CONTEMPORARY CARTOGRAPHY. Edited by D. R. F raser T aylor . John Wiley and Sons, Lid. New York , 1980.
GEOLOGICAL AND TOPOGRAPHIC MAPPING FROM AERIAL PHOTOGRAPHS. By K. S. D ueholm and numerous other authors. Meddelelse 10, Instituttet for Landmåling og Fotogrammetri, Danmarks Tekniski Højskole , 1979.
PHOTOGRAMMETRY. By F. H. M offitt and E. M. M ikhail . Third edition. Harper and Row, New York , 1980.
ADVANCED PHYSICAL GEODESY. By H. M oritz . Herbert Wichmann Verlag. Karlsruhe and Abacus Press, Tunbridge Wells , 1980.
PAPERS WRITTEN IN HONOR OF THE 70TH BIRTHDAY OF PROFESSOR LUIGI SOLAINI. Ricerche di Geodesia, Topografia e Fotogrammetria, No. 1. Cooperativa Libraria Universitaria del Politecnico on behalf of Institute di Topografia, Fotogrammetria e Geofisica, Politecnico de Milano , 1979.
INTERNATIONAL JOURNAL OF REMOTE SENSING, Volume 1, Number 1, January-March, 1980. Quarterly. Taylor & Francis Ltd. London.