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Global characteristics of the second-order ionospheric delay error using inversion of electron density profiles from COSMIC occultation data

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Science China(Physics,Mechanics & Astronomy) 2014年第2期57卷 365-374页

作者： WANG Hu WANG Cheng WANG JieXian DANG YaMing BAI GuiXia WANG QianXin Chinese Academy of surveying and Mapping department of surveying and Geo-informatics TongJi University department of Electrical and Computer Engineering Miami University

It is a well known fact that ionospheric delay error is a predominant factor which influences the positioning accuarcy of *** the main part of the first-order ionospheric delay error can be removed by the frequency-dependent behaviors of the ionosphere,the second-order ionospheric delay error must be eliminated to achieve millimetre-scale positioning *** to COSMIC occultation providing electron density profiles on the global scale,the paper presents the first-order and the second-order ionospheric delay error analysis on the global scale using the inversion of electron density profiles from COSMIC occultation data during 2009–***,because of the special geographical location of three ISR(incoherent scatter radar),the first-order and the second-order ionospheric delay errors are calculated and discussed;the paper also shows and analyzes the diurnal,seasonal,semi-annual variation of ionospheric delay error with respect to signal *** show that for the L1 signal path,the first-order ionospheric delay error is the largest near the equator,which is circa 7 m;the maximum second-order ionospheric delay error are circa 0.6 cm,0.8 cm and 0.6 cm respectively for L1 signals coming from the zenith,the north and the south at 10 degree elevation *** second-order ionospheric delay error on the L1 signal path from zenith are the symmetry between 15°and 15°with respect to magnetic equator,and are nearly zero at the magnetic *** the first time,the second-order ionospheric delay error on the global scale is presented,so this research will greatly contribute to analysing the higher-order ionospheric delay error characteristics on the global scale.

关键词： ionosphere GPS COSMIC ISR IGRF

Global precision analysis of carrier phase relative positioning in BeiDou navigation satellite system and United States global positioning system

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Science China Earth Sciences 2019年第4期62卷 733-749页

作者： Letao ZHOU Dingfa HUANG Wei FENG Wu CHEN Xi ZHANG Li YAN department of surveying and Geo-Informatics Faculty of Geosciences and Environmental EngineeringSouthWest JiaoTong University department of Land surveying and Geo-Informatics Hong Kong Polytechnic University

In this paper, we derived a high-efficiency formula for calculating the precision of carrier phase relative positioning,analyzed the various factors that affect the positioning accuracy using the carrier phase, and proposed the concept of using a frequency dilution of precision to describe the quantitative effect of different frequency combinations on the positioning precision. To this end, we computed and plotted the global spatial distribution map of the relative positioning dilution of precision for single-day solution, half-hour solution, and single-epoch solution of the global positioning system(GPS), regional Beidou navigation satellite system(BDS2), future global Beidou navigation satellite system(BDS3), and their fusion *** processing software with autonomous intellectual property rights(GCN and VENUS/ARSNet), we solved the measurement data and examined the positioning precision of the single-day solution and single-epoch solution of GPS and *** analysis demonstrated that the B1/B2 frequency positioning precision of BDS2 was better than that of L1/L2 frequency positioning of GPS, but the positioning precision of the BDS2 is worse than that of GPS over most of the service region of the BDS2. Further, the positioning precision of BDS3 is better than that of GPS in the Asia-Pacific region, while it is the opposite in other regions. Based on these conclusions, we put forth some optimization recommendations regarding the signal frequency of the navigation system and GPS measurement standards to serve as references for optimizing the system performance and formulating standards.

关键词： BeiDou navigation satellite system Relative positioning Dilution of precision Frequency dilution of precision Spatial-temporal availability

A general method of spatio-temporal clustering analysis

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Science China(Information Sciences) 2013年第10期56卷 158-171页

作者： DENG Min LIU QiLiang WANG JiaQiu SHI Yan department of surveying and Geo-informatics Central South University

Spatio-temporal clustering has been a hot topic in the feld of spatio-temporal data mining and knowledge *** can be employed to uncover and interpret developmental trends of geographic phenomenon in the real ***,existing spatio-temporal clustering methods seldom consider both spatiotemporal autocorrelations and heterogeneities among spatio-temporal entities,and the coupling in space and time has not been well *** this paper,a unifed framework for the clustering analysis of spatio-temporal data is proposed,and a novel spatio-temporal clustering algorithm is developed by means of a spatio-temporal statistics methodology and intelligence computation *** method is applied successfully to fnding spatio-temporal cluster in China’s annual temperature database for the period 1951 1992.

关键词： spatio-temporal clustering spatio-temporal autocorrelation spatio-temporal heterogeneity spatio-temporal data mining

Assessment of GNSS zenith tropospheric delay responses to atmospheric variables derived from ERA5 data over Nigeria

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Satellite Navigation 2023年第1期4卷 167-182,I0005页

作者： Ifechukwu Ugochukwu Nzelibe Herbert Tata Timothy Oluwadare Idowu department of surveying and Geoinformatics Federal University of Technology AkureAkureNigeria

Tropospheric delay is a major error caused by atmospheric refraction in Global Navigation Satellite System(GNSS)*** study evaluates the potential of the European Centre for Medium-range Weather Forecast(ECMWF)Reanalysis 5(ERA5)atmospheric variables in estimating the Zenith Tropospheric Delay(ZTD).Linear regression models(LRM)are applied to estimate ZTD with the ERA5 atmospheric *** ZTD are also estimated using standard ZTD models based on ERA5 and Global Pressure and Temperature 3(GPT3)atmospheric *** ZTD estimates are evaluated using the data collected from the permanent GNSS continuously operating reference stations in the Nigerian *** results reveal that the Zenith Hydrostatic Delay(ZHD)from the LRM and the Saastamoinien model using ERA5 surface pressure are of identical accuracy,having a Root Mean Square(RMS)error of 2.3 mm while the GPT3-ZHD has an RMS of 3.4 *** the Zenith Wet Delay(ZWD)component,the best estimates are derived using ERA5 Precipitable Water Vapour(PWV).These include the ZWD derived by the LRM having an average RMS of 20.9 mm and Bevis equation having RMS of 21.1 mm and 21.0 mm for global and local weighted mean temperatures,*** evaluation of GPT3-ZWD estimates gives RMS of 45.8 *** study has provided a valuable insight into the application of ERA5 data for ZTD *** line with the fndings of the study,the ERA5 atmospheric variables are recommended for improving the accuracy in ZTD estimation,required for GNSS positioning.

关键词： ECMWF reanalysis 5(ERA5) Global navigation satellite systems(GNSS) Global pressure and temperature 3(GPT3) Modelling Nigeria Zenith tropospheric delay(ZTD)

Assessing the adequacy and sustainability performance of multi-family residential buildings in Anambra State,Nigeria

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Regional Sustainability 2021年第1期2卷 23-35页

作者： Peter Uchenna Okoye Chukwuemeka Ngwu department of building Nnamdi Azikiwe UniversityAwka420007Nigeria department of Quantity surveying Nnamdi Azikiwe UniversityAwka420007Nigeria

The proliferation of multi-family residential building in Anambra State of Nigeria due to increasing demand without recourse to performance has broughtconcerns about the adequacy and sustainability of this housing *** study therefore,assessed the adequacy and sustainability performance of multi-family residential buildings in urban areas of Anambra *** study sampled the opinions of 384 households living in multi-family residential buildings through a questionnaire *** conducted data analysis based on 214 responses that were useful for *** study found that internal and building component variables and supporting neigh-borhood variables were adequate,but the surrounding environment variables were inadequate based on Mean Score ***,based on Sustainability Performance Index,the occupant sperceived social sustainability performance of the buildings as satisfactory,while environmental and economic sustainability performance were perceived as fairly *** Pearson correlation coefficient result further established that adequacy of internal and building component variables was significantly and positively related to the residents'perceived social sustainability *** of the surrounding environmental variables was also found to be positively and significantly related to the residents'perceived environmental sustainability performance,whereas adequacy of supporting neighborhood facilities was found to be negatively and significantly related to the residents’perceived economic sustainability *** sug-gested that investors and owners of multi-family residential buildings should direct more efforts towards improving the surrounding environment to supplements other facilities and increase the economic benefit of the renters or occupiers with increasing economic sustainability performance in terms of value for money.

关键词： Adequacy level Economic sustainability Environmental sustainability Social sustainability Multi-family residential building Residential building

A novel vehicle navigation map matching algorithm based on fuzzy logic and its application

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Journal of Central South University of Technology 2005年第2期12卷 214-219页

作者：童小华吴颂春吴淑琴刘大杰 department of surveying and Geoinformatics Tongji University Shanghai 200092 China

A new real-time map matching algorithm based on fuzzy logic is proposed. 3 main factors affecting the reliability of map matching, including the distance between the vehicle location and the matching road segment, the angle between the vehicle direction and the road segment direction and the road connectivity are discussed. Fuzzy rules for the distance, angle and connectivity are presented to calculate the matching reliability. 2 indicators for estimating the matching reliability are then derived, one is the lower limit of the reliability, and the other is the limit error of the difference between the maximal value and the second-maximal value of the reliability. A real-time map-matching system based on fuzzy logic is therefore developed. Using the real data of global positioning system(GIS) based navigation and geographic information system(GPS) based road map, the method is verified and the (results) prove the effectiveness of the proposed method.

关键词： map matching fuzzy logic reliability GPS GIS road network

Bundle adjustment for data processing of theodolite industrial surveying system

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中国有色金属学会会刊：英文版 2001年第2期11卷 307-310页

作者：邹峥嵘丁晓利曾卓乔何凭宗 department of surveying Engineering Central South UniversityDepartment of Land Surveying and Geo-Informatics Hong Kong Polytechnic UniversityHunghom Hong Kong department of Land surveying and Geo-Informatics Hong Kong Polytechnic UniversityHunghom Hong Kong department of surveying Engineering Central South University

The photogrammetric bundle adjustment was used in data processing of electronic theodolite industrial surveying system by converting angular observations into virtual photo coordinates. The developed algorithm has ability of precision estimation and data snooping, do not need initial values of exterior orientation elements and object point coordinates. The form of control condition for the system is quite flexible. Neither centering nor leveling is the theodolite needed and the lay out of theodolite position is flexible when the system is used for precise survey. Experiments carried out in test field verify the validity of the data processing method. [

关键词： electronic theodolite industrial surveying system bundle adjustment

Assessment of energy utilization and leakages in buildings with building information model energy

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Frontiers of Architectural Research 2017年第1期6卷 29-41页

作者： Egwunatum I. Samuel Esther Joseph-Akwara Akaigwe Richard department of Quantity surveying Delta State Polytechnic Ozoro 334111 Nigeria department of Civil Engineering Delta State Polytechnic Ozoro 334111 Nigeria department of building PIc Lagos State Nigeria

Given the ability of building information models （BIM） to serve as a multidisciplinary data repository, this study attempts to explore and exploit the sustainability value of BIM in delivering buildings that require less energy for operations, emit tess carbon dioxide, and provide conducive living environments for occupants. This objective was attained by a critical and extensive literature review that covers the following：（1） building energy consumption, （2） building energy performance and analysis, and （3） BIM and energy assessment. Literature cited in this paper shows that linking an energy analysis toot with a BIM model has helped project design teams to predict and create optimized energy consumption by conducting building energy performance analysis utilizing key performance indicators on average thermal transmitters, resulting heat demand, lighting power, solar heat gains, and ventilation heat losses. An in-depth analysis was conducted on a completed BIM integrated construction project utilizing the Arboleda Project in the Dominican Republic to validate the aforementioned findings. Results show that the BIM-based energy analysis helped the design team attain the world＇s first positive energy building. This study concludes that linking an energy analysis tool with a BIM model helps to expedite the energy analysis process, provide more detailed and accurate results, and deliver energy-efficient buildings. This study further recommends that the adoption of level 2 BIM and BIM integration in energy optimization analysis must be demanded by building regulatory agencies for all projects regardless of procurement method （i.e., government funded or otherwise） or size.

关键词： building informationmodeling building energy per-formance analysis Sustainability Energy efficiency

Dynamic model for landsliding monitoring under rigid body assumption

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中国有色金属学会会刊：英文版 2001年第2期11卷 301-306页

作者：朱建军丁晓利陈永奇 department of surveying Engineering Central South University department of Land surveying and Geo-Informatics Hong Kong Polytechnic University Kowloon Hong Kong

Based on the assumption that the slope bodies are rigid, the dynamic model of the landsiding (forward model) was put forward. According to the dynamic model, the system equations of Kalman filter were constituted. The mechanical status of a slope was hence combined with the monitoring data by Kalman filter. The model uncertainties or model errors could also be considered through some fictitious observation equations. Different from existed methods, the presented method can make use for not only the statistic information contained in the data but also the information provided by the mechanical and geological aspect of slopes. At last a numerical example was given out to show the feasibility of the method. [

关键词： dynamic model Kalman filter rigid body landslide monitoring