Geodetic data inversion based on Bayesian formulation with direct and indirect prior information     

Mitsuhiro Matsu'ura  Akemi Noda  Yukitoshi Fukahata 《Geophysical Journal International》2007,171(3):1342-1351

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由空间直角坐标计算大地坐标的简便公式     

张华海  郑南山  王军  李景芝 《全球定位系统》2002,27(4):9-12

对大地测量教科书中给出的空间三维直角坐标与大地坐标的转换公式进行了大量的计算与分析，总结得出一组由空间直角坐标计算大地坐标的简便公式。  相似文献   

Gauss-Markov模型参数的岭型广义逆估计及其优良性     

归庆明  郭建锋 《测绘科学》2002,(3)

本文继续文献 [10 ]的工作 ,进一步讨论了测量平差 Gauss- Markov模型参数岭型广义逆估计的若干性质 ,如允许性、优效性、相对效率、抗干扰性等等 ,得到了许多重要结论。计算结果表明 ,在设计阵呈病态时 ,岭型广义逆估计确能明显改善 L S估计  相似文献   

Lunar Laser Ranging: Glorious Past And A Bright Future   总被引：1，自引：0，他引：1  

Peter J. Shelus 《Surveys in Geophysics》2001,22(5-6):517-535

Lunar Laser Ranging (LLR), a part of the NASA Apollo program, has beenon-going for more than 30 years. It provides the grist for a multi-disciplinarydata analysis mill. Results exist for solid Earth sciences, geodesy and geodynamics,solar system ephemerides, terrestrial and celestial reference frames, lunar physics,general relativity and gravitational theory. Combined with other data, it treatsprecession of the Earth's spin axis, lunar induced nutation, polar motion/Earthrotation, Earth orbit obliquity to the ecliptic, intersection of the celestial equatorwith the ecliptic, luni-solar solid body tides, lunar tidal deceleration, lunar physicaland free librations, structure of the moon and energy dissipation in the lunar interior.LLR provides input to lunar surface cartography and surveying, Earth station and lunar retroreflector location and motion, mass of the Earth-moon system, lunar and terrestrial gravity harmonics and Love numbers, relativistic geodesic precession, and the equivalence principle of general relativity. With the passive nature of the reflectors and steady improvement in observing equipment and data analysis, LLR continues to provide state-of-the-art results. Gains are steady as the data-base expands. After more than 30 years, LLR remains the only active Apollo experiment. It is important to recognize examples of efficient and cost effective progress of research. LLR is just such an example.  相似文献   

Rotation and dilation deformation mechanisms for auxetic behaviour in the α-cristobalite tetrahedral framework structure     

A. Alderson  K. E. Evans 《Physics and Chemistry of Minerals》2001,28(10):711-718

 Analytical expressions are derived for the Poisson's ratios associated with a three-dimensional network of regular, corner-sharing tetrahedra in which: (1) the tetrahedra are assumed to be rigid and free to rotate relative to each other; (2) the tetrahedra are assumed to maintain shape and orientation but are free to change size (dilate); (3) tetrahedral rotation and dilation are assumed to act concurrently. The structure has a primitive unit cell containing four tetrahedra and is analogous to the molecular structure of α-cristobalite. Strain-dependent variations in Poisson's ratio are also predicted by the models. For deformation due to tetrahedral rotation the network is found to exhibit negative Poisson's ratios in each of the three principal directions, with the magnitude of the Poisson's ratio being dependent on the angle of rotation of the tetrahedra. The behaviour of the Poisson's ratio is isotropic in the transverse plane, but anisotropic elsewhere. In the dilation model negative Poisson's ratios equal to −1 are observed for uniaxial loading in any of the principal directions, with the value being constant irrespective of tetrahedral size. The model for concurrent tetrahedral rotation and dilation allows positive as well as negative Poisson's ratios, with the values determined by the framework geometry and relative strengths of the two mechanisms. The concurrent model also offers a design route to materials and structures having ultrahigh Young's moduli. Received: 15 February 2000 / Accepted: 1 October 2000  相似文献   

空间网联合处理中地壳运动参数的引入     

吕志平 《测绘学报》1996,25(2):146-150

本文阐述了空间大地网联合处理中的地壳运动模型的建立方法，并在此基础上提出了非均匀形变，均匀形变，体应变和刚体转动的识别方法，文中以我国现有空间大地网的模拟数据，结合中国大陆地壳构造进行了试算。  相似文献   

Water-soluble organics in atmospheric particles: A critical review of the literature and application of thermodynamics to identify candidate compounds   总被引：15，自引：0，他引：15  

Pradeep Saxena  Lynn M. Hildemann 《Journal of Atmospheric Chemistry》1996,24(1):57-109

Although organic compounds typically constitute a substantial fraction of the fine particulate matter (PM) in the atmosphere, their molecular composition remains poorly characterized. This is largely because atmospheric particles contain a myriad of diverse organic compounds, not all of which extract in a single solvent or elute through a gas chromatograph; therefore, a substantial portion typically remains unanalyzed. Most often the chemical analysis is performed on a fraction that extracts in organic solvents such as benzene, ether or hexane; consequently, information on the molecular composition of the water-soluble fraction is particularly sparse and incomplete.This paper investigates theoretically the characteristics of the water-soluble fraction by splicing together various strands of information from the literature. We identify specific compounds that are likely to contribute to the water-soluble fraction by juxtaposing observations regarding the extraction characteristics and the molecular composition of atmospheric particulate organics with compound-specific solubility and condensibility for a wide variety of organics. The results show that water-soluble organics, which constitute a substantial fraction of the total organic mass, include C2 to C7 multifunctional compounds (e.g., diacids, polyols, amino acids). The importance of diacids is already recognized; our results provide an impetus for new experiments to establish the atmospheric concentrations and sources of polyols, amino acids and other oxygenated multifunctional compounds.  相似文献   

伸展地区铲式正断层作用及其大地测量观测   总被引：1，自引：1，他引：1  

桂Kun长 《地质论评》1993,39(3):196-204

铲式正断层作用是伸展构造区最主要的构造运动形式。本文根据铲式正断层作用的几何学、运动学特征,结合华北平原伸展区大地测量观测成果,探讨伸展区构造形变铲式正断层现今活动的地表形变效应及其动态特征。  相似文献   

Numerical analysis model of horizontal displacement of active faults     

De-Han Zhang 《地震学报(英文版)》1993,6(3):601-608

In this paper, a numerical model was presented for interpreting the movement feature of an active fault zone. This model was based on the analytic solution, given by Crouch (Crouch, 1976), for the problem of displacement discontinuity in an infinite elastic solid, making full use of geodetic and geological data and it was constructed by the boundary element method. A numerous test computation shows that if you want to catch the possible seismic precursor from the displacement’s vector, you have to associate the computation with geological survey in a deep going way, otherwise you would fail in your propose. This method is valid for analysing the zone of strike-slip fault and it has some values for dealing with other analogous problems. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 153–158, 1993.  相似文献   

Geospatial technologies for Chang’e-3 and Chang’e-4 lunar rover missions     

Kaichang Di  Zhaoqin Liu  Wenhui Wan  Man Peng  Bin Liu  Yexin Wang 《地球空间信息科学学报》2020,23(1):87-97

ABSTRACT

This paper presents a brief overview of the geospatial technologies developed and applied in Chang’e-3 and Chang’e-4 lunar rover missions. Photogrammetric mapping techniques were used to produce topographic products of the landing site with meter level resolution using orbital images before landing, and to produce centimeter-resolution topographic products in near real-time after landing. Visual positioning techniques were used to determine the locations of the two landers using descent images and orbital basemaps immediately after landing. During surface operations, visual-positioning-based rover localization was performed routinely at each waypoint using Navcam images. The topographic analysis and rover localization results directly supported waypoint-to-waypoint path planning, science target selection and scientific investigations. A GIS-based digital cartography system was also developed to support rover teleoperation.  相似文献