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The precise multimode GNSS positioning for UAV and its application in large scale photogrammetry

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Geo-Spatial Information Science 2016年第3期19卷 188-194页

作者： Hongxing Sun Leilei Li Xuewen Ding Bingxuan Guo state key laboratory of Information Engineering in surveying Mapping and Remote SensingWuhan UniversityWuhanChina College of Aerospace Engineering Chongqing UniversityChongqingChina

In this paper,we use multimode GNSS instead of single GPS constellation to resolve the three exterior line elements of each *** principles of differential GNSS positioning and GNSSsupported aerial triangulation(AT)are presented and an implementation case is *** multi-constellation system,the number of visible satellites is significantly increased and the geometry distribution of the satellites is well *** positioning accuracy and robustness are therefore getting better compared to GPS *** results show that differential GNSS has remarkable increment on the integer rate of ambiguity solution when GPS has few number and low elevation angle of *** combined AT adjustment of GNSS resolution and 10 ground control points(GCPs)achieve the horizontal accuracy of±18 cm and vertical accuracy of±23 cm for the check points,which are comparable with traditional bundle adjustment with dense GCPs and better than GPS-supported *** achieved accuracy also satisfies the requirement for 1:500 topographic maps with the bonus of 84%GCPs *** conclusion,GNSS-supported AT is of feasibility and superiority for large scale Unmanned Aerial Vehicle-based photogrammetry.

关键词： Multi-constellation differential GNSS UAV photogrammetry GNSS-supported aerial triangulation

Performance and analytical modelling of halo-doped surrounding gate MOSFETs

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Chinese Physics B 2008年第11期17卷 4312-4317页

作者：李尊朝 Department of Microelectronics School of Electronics and InformationEngineering Xi’an Jiaotong University

Halo structure is added to sub-100 nm surrounding-gate metal-oxide-semiconductor fieldeffect-transistors （MOS- FETs） to suppress short channel effect. This paper develops the analytical surface potential and threshold voltage models based on the solution of Poisson＇s equation in fully depleted condition for symmetric halo-doped cylindrical surrounding gate MOSFETs. The performance of the halo-doped device is studied and the validity of the analytical models is verified by comparing the analytical results with the simulated data by three dimensional numerical device simulator Davinci. It shows that the halo doping profile exhibits better performance in suppressing threshold voltage roll-off and drain-induced barrier lowering, and increasing carrier transport efficiency. The derived analytical models are in good agreement with Davinci.

关键词： MOSFET surrounding gate compact model halo

Algebraic encoding scheme for aperture 3 hexagonal discrete global grid system

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Science China Earth Sciences 2018年第2期61卷 215-227页

作者： BEN Jin LI YaLu ZHOU ChengHu WANG Rui DU LingYu Institute of surveying and Mapping Information Engineering University state key laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences College of Earth Science and surveying Engineering China University of Mining and Technology (Beijing)

Discrete Global Grid Systems(DGGSs) are spatial references that use a hierarchical tessellation of cells to partition and address the entire globe. They provide an organizational structure that permits fast integration between multiple sources of large and variable geospatial data sufficient for visualization and analysis. Despite a significant body of research supporting hexagonal DGGSs as the superior choice, the application thereof has been hindered owing in part to the lack of a rational hierarchy with an efficient addressing system. This paper presents an algebraic model of encoding scheme for the Aperture 3 Hexagonal(A3H) DGGS. Firstly, the definition of a grid cell, which is composed of vertices, edges, and a center, is introduced to describe fundamental elements of grids. Secondly, by identifying the grid cell with its center, this paper proves that cell centers at different levels can be represented exactly using a mixed positional number system in the complex plane through the recursive geometric relationship between two successive levels, which reveals that grid cells are essentially special complex radix numbers. Thirdly, it is shown that through the recursive geometric relationship of successive odd or even levels, the mixed positional number system can also be applied to uniquely represent cell centers at different levels under specific constraint conditions, according to which the encoding scheme is designed. Finally, it is shown that by extending the scheme to 20 triangular faces of the regular icosahedron,multi-resolution grids on closed surfaces of the icosahedron are addressed perfectly. Contrast experiments show that the proposed encoding scheme has the advantages of theoretical rigor and high programming efficiency and that the efficiency of cross-face adjacent cell searching is 242.9 times that of a similar scheme. Moreover, the proposed complex radix number representation is an ideal formalized description tool for grid systems. The research i

关键词： Discrete Global Grid System Hexagon Positional number system Algebraic encoding

Post-earthquake assessment of building damage degree using LiDAR data and imagery

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Science China(Technological Sciences) 2008年第S2期51卷 133-143页

作者： LI ManChun1,CHENG Liang1,2,GONG JianYa2,LIU YongXue1,CHEN ZhenJie1,LI FeiXue1,CHEN Gang1,CHEN Dong1 & SONG XiaoGang3 1 Department of Geographic Information Science,Nanjing University,Nanjing 210093,China 2 state key laboratory of Information Engineering in surveying,Mapping and Remote Sensing,Wuhan University,Wuhan 430079,China 3 state key laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China Department of Geographic Information Science Nanjing University Nanjing China state key laboratory of Information Engineering in surveying Mapping and Remote Sensing Wuhan University Wuhan China state key laboratory of Earthquake Dynamics Institute of Geology China Earthquake Administration Beijing China

Various methods have been developed to detect and assess building's damages due to earthquakes using remotely sensed *** the launch of the high resolution sensors such as IKONOS and QuickBird,it becomes realistic to identify damages on the scale of individual *** the low accuracy of the results has often led to the use of visual interpretation ***,it is very difficult to estimate the degree of building damage(*** damage,moderate damage,or severe damage) in detail using the existing ***,a novel approach integrating LiDAR data and high resolution optical imagery is proposed for evaluating building damage degree *** approach consists of two steps:3D building model reconstruction and rooftop patch-oriented 3D change ***,a method is proposed for automatically reconstructing 3D building models with precise geometric position and fine details,using pre-earthquake LiDAR data and high resolution ***,focusing on each rooftop patch of the 3D building models,the pre- and post-earthquake LiDAR points belonging to the patch are collected and compared to detect whether it was destroyed or not,and then the degree of building damage can be identified based on the ratio of the destroyed rooftop patches to all rooftop *** novelty of the proposed approach is to detect damages on the scale of building's rooftop patch and realize quantitative estimation of building damage degree.

关键词： post-earthquake assessment building damage degree rooftop patch LiDAR imagery

High-accuracy topographical information extraction based on fusion of ASTER stereo-data and ICESat/GLAS data in Antarctica

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Science China Earth Sciences 2009年第5期52卷 714-722页

作者： E DongChen1,3,SHEN Qiang2,XU Ying1,3 & CHEN Gang4 1 Chinese Antarctic Center of surveying and Mapping,Wuhan University,Wuhan 430079,China 2 Institute of Seismology China Earthquake Administration,Wuhan 430071,China 3 key laboratory of Polar surveying and Mapping,state Bureau of surveying and Mapping,Wuhan University,Wuhan 430079,China 4 Department of Geography,University of Calgary,Calgary,Alberta T2N 1N4,Canada Chinese Antarctic Center of surveying and Mapping Wuhan University Wuhan China key laboratory of Polar surveying and Mapping State Bureau of Surveying and Mapping Wuhan University Wuhan China Institute of Seismology China Earthquake Administration Wuhan China Department of Geography University of Calgary Calgary Canada

In order to better support Antarctic inland ice sheet expedition from Zhongshan Station to Dome A,the topographic data are *** present,although the entire Antarctic DEM provided by RAMP(Ra-darsat Antarctic Mapping Project) was estimated at the highest horizontal(spatial) resolution of about 200 m,the real horizontal resolution of the DEM varies from place to place depending on the density and scale of the original source *** ice shelves and the inland ice sheet,the horizontal resolution is about 5 km;the vertical accuracy is estimated to be ±50 m in interior East Antarctic ice sheet and away from the mountain ***,more accurate topographic data are unavailable in *** order to meet the requirements of high-accuracy topographic information for further researches,this paper mainly addresses a fusion study of ASTER stereo pairs and ICESat/GLAS altimetry data for extraction of high-accuracy DEM in East Antarctica,based on the high horizontal resolution(15 m) of ASTER and vertical accuracy(13.8 cm) of ICESat/***,some altimetry data were selected as vertical control points to reduce errors of image correlation matching during the extraction of ASTER-based ***,ice sheet altimetry data derived from ICESat were used to generate DEM ranging from 75° to 81°S because existing ASTER data do not cover this area and high density of the coverage of ICESat altimetry ***,the DEM in coverage of the expedition route was *** analysis of result reveals that the DEM accuracy is improved *** absolute vertical accuracy of DEM is higher than 15 m in some cases and higher than 30 m for all the areas along the expedition route except from the 009-001 scene;the interior accuracy is higher than 15 m and higher than 7 m in some *** can meet the requirements of topographic map at 1:50000 scale,which is an economic and advantageous method to produce the topographic products.

关键词： DEM Antarctica Zhongshan Station Dome A ASTER ICESat GLAS

A motion correction on direct estimations of air-sea fluxes from a buoy

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Acta Oceanologica Sinica 2013年第3期32卷 63-70页

作者： HUANG Yansong SONG Jinbao FAN Conghui key laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences South China Sea Marine Engineering surveying Center State Oceanic Administration

A flux system deployed on a moored buoy has been described, which is capable of directly estimating the airsea fluxes after removing the contamination in the signal due to buoy motion. A triple loop fitting method has been demonstrated for determining the three angular offsets between measurement axes of the sonic anemometer and motion pack. The data collected in an experiment in the Northern Huanghai Sea is used to correct the three sonic anemometer measurements of turbulent wind for buoy motion. The effective removal of wave-scale motion from the spectra and cospectra are demonstrated. Estimates of along-wind momentum flux, sensible heat flux and latent heat flux calculated by the eddy correlation method based on data obtained by sonic anemometer 81000V are shown to be in the same trend and scale with those determined by the bulk aerodynamic method after motion correction. The motion correction not only greatly improve the estimation of the momentum flux but also has a great impact on the calculated sensible heat flux.

关键词： air-sea fluxes motion correction angular offset eddy correlation method bulk aerodynamicmethod

Influence of geological factors on coal permeability in the Sihe coal mine

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International Journal of Coal Science & Technology 2022年第1期9卷 58-70页

作者： Guangui Zou Qianhua Zhang Suping Peng Jiasheng She Deliang Teng Chaochao Jin Yuyan Che state key laboratory of Coal Resources and Safe Mining BeijingChina College of Geoscience and surveying Engineering China University of Mining&TechnologyBeijingChina

Permeability of coal reservoirs influence the extraction of coal gas from coal *** coal samples were collected at an anticline and a syncline of the No.3 coal seam in the Sihe coal ***,permeability,pore size,vitrinite reflectance,and liquid nitrogen adsorption of the samples were *** curvatures at the sample locations,and the distance between the sampling locations and the nearest faults were calculated based on seismic *** influences of the evaluated parameters on permeability were *** factors that influence permeability of the No.3 coal seam were extracted using principal component analysis(PCA).Based on the porosity–permeability model derived from the Archie formula and classic Kozeny–Carman equation,we deduced that the permeability of coal increased with an increase in *** an increase in average vitrinite reflectance,permeability decreases first and then *** results showed that coal permeability was regulated by three key components representing three *** first component included pore size,depth,and pore complexity accounting for 52.59%of the variability indicating that it was the most important in controlling *** second component included specific surface area,structural curvature,and porosity,and the third component comprised of specific surface area,porosity,and average vitrinite ***,pore diameter and complexity had significant effects on coal *** results show that researchers and stakeholders must consider the interactions among multiple factors rather than single factors to understand the influences on permeability to facilitate efficient utilization of coalbed methane resources.

关键词： Coal mine Permeability Geological factors Principal component analysis

Layout graph model for semantic façade reconstruction using laser point clouds

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Geo-Spatial Information Science 2021年第3期24卷 403-421页

作者： Hongchao Fan Yuefeng Wang Jianya Gong Department of Civil and Environmental Engineering Norwegian University of Science and TechnologyTrondheimNorway state key laboratory of Information Engineering in surveying Mapping and Remote SensingWuhan UniversityWuhanChina

Building façades can feature different patterns depending on the architectural style,function-ality,and size of the buildings;therefore,reconstructing these façades can be *** particular,when semantic façades are reconstructed from point cloud data,uneven point density and noise make it difficult to accurately determine the façade *** inves-tigating façade layouts,Gestalt principles can be applied to cluster visually similar floors and façade elements,allowing for a more intuitive interpretation of façade *** propose a novel model for describing façade structures,namely the layout graph model,which involves a compound graph with two structure *** the proposed model,similar façade elements such as windows are first grouped into clusters.A down-layout graph is then formed using this cluster as a node and by combining intra-and inter-cluster spacings as the ***,a top-layout graph is formed by clustering similar *** extracting relevant parameters from this model,we transform semantic façade reconstruction to an optimization strategy using simulated annealing coupled with Gibbs *** façade point cloud data with different features were selected from three datasets to verify the effectiveness of this *** experimental results show that the proposed method achieves an average accuracy of 86.35%.Owing to its flexibility,the proposed layout graph model can deal with different types of façades and qualities of point cloud data,enabling a more robust and accurate reconstruc-tion of façade models.

关键词： Building façade semantic reconstruction point cloud compound graph model stochastic process

Mining subsidence control by solid backfilling under buildings

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中国有色金属学会会刊：英文版 2011年第S3期21卷 670-674页

作者： ZHA Jian-feng1, 2, 3, GUO Guang-li1, 2, FENG Wen-kai3, WANG Qiang1, 2 1. key laboratory for Land Environment and Disaster Monitoring of the state Bureau of surveying and Mapping, China University of Mining and Technology, Xuzhou 221116, China 2. Jiangsu key laboratory of Resources and Environmental Information Engineering, China University of Mining and Technology, Xuzhou 221116, China 3. state key laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China key laboratory for Land Environment and Disaster Monitoring of the state Bureau of surveying and Mapping China University of Mining and Technology Xuzhou 221116 China Jiangsu key laboratory of Resources and Environmental Information Engineering China University of Mining and Technology Xuzhou 221116 China state key laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu 610059 China

Solid backfilling mining can reduce the buildings' damage caused by mining greatly. The reduction of subsidence value, the slow advancing speed and the subsidence caused by backfilling body compaction are the main reasons that solid backfilling mining velocity decreases significantly. Based on the research of mechanism, some principles on subsidence control of solid backfilling mining under buildings were proposed. The equivalent mining height was designed according to the fortification criteria of buildings and their attachment structures, which enables the ground movement and deformation caused by mining to be less than the corresponding fortification criteria.

关键词： solid backfilling mining subsidence control mining under buildings