Loading...

Table of Content

    25 June 2018, Volume 0 Issue 6
    GPS Satellite Clock Bias Prediction Method Considering Random Items of Clocks Bias
    YU Ye, ZHANG Huijun, LI Xiaohui
    2018, 0(6):  1-6.  doi:10.13474/j.cnki.11-2246.2018.0166
    Asbtract ( )   HTML   PDF (1417KB) ( )  
    References | Related Articles | Metrics
    Based on the characteristics of the trend and random items of the satellite clock bias(SCB),a combination prediction model based on grey model(GM(1,1)) and Autoregressive Integrated Moving Average(ARIMA) is proposed.First,the model uses GM (1,1) to predict the trend of SCB.Then,the residual sequence of GM(1,1) model is modeled and predicted by using the ARIMA.Finally,the prediction results of GM (1,1) and ARIMA are added to obtain the final prediction value of clock bias.In addition,the predictive tests are carried out by using the precision SCB published by IGS(International GNSS Service),and the results are compared with those of the quadratic polynomial model(QPM)commonly used in SCB forecast and using the modified exponential curve method (MECM).The results show that this method can make high-precision short-term and mid-term forecast of GPS SCB.When modeling with 12 h clock bias data to predict the next 6,12,18 and 24 h,the average prediction accuracy of the model we proposed is 0.71,1.17,1.93 and 4.38 ns,respectively.Compared with the mean prediction accuracy of QPM,the accuracy of the prediction was increased by 29.70%,43.75%,67.62% and 76.21%,respectively.Compared with the mean prediction accuracy of MECM,the accuracy of the prediction was increased by 18.39%,33.90%,61.40% and 70.49%,respectively.
    Research on Multisystem Fusion Global Ionospheric Modeling
    WANG Jian, DANG Yamin, WANG Hu, ZHANG Longping, LIU Zongqiang, HAN Hengxing
    2018, 0(6):  7-11.  doi:10.13474/j.cnki.11-2246.2018.0167
    Asbtract ( )   HTML   PDF (5090KB) ( )  
    References | Related Articles | Metrics
    In recent years,the construction and application of BDS in China have brought new opportunities and challenges for the study of the GNSS ionosphere.Based on the data from iGMAS analysis center of Chinese Academy of Surveying and Mapping,a global system of ionospheric spherical harmonic function is built up by three systems,and the results are analyzed.The research shows that the poor performance of marine areas removed in the mainland,multisystem integration of global ionospheric modeling results can accurately express the ionospheric VTEC;the accuracy of statistical results of code deviation DCB contrast three system,GPS satellite system C1P2 code deviation is less than 1ns,most of the highest accuracy within 0.5 ns,GLONASS satellite;C1P2 code deviation is less than 2 ns,the accuracy is slightly lower than the GPS system;BDS satellite system B1B2 code deviation is less than 1 ns,the precision is slightly higher than the GLONASS system,but GPS has better stability,with the product code deviation of daily variation is large,may cause the constellation structure of the BDS system is not perfect.
    Characteristics Analysis of GNSS Data Quality in Polar Region
    ZUO Zong, CHEN Mingjian, LI Ying, YAO Xiang
    2018, 0(6):  12-16,67.  doi:10.13474/j.cnki.11-2246.2018.0168
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    In order to clarify the influence of polar environment on the quality of BeiDou satellite data and satellite navigation and positioning services,all the BeiDou satellite observation data acquired in IGS stations and the observations of Zhongshan station are used to analyze the BDS data quality characteristics in the polar region,combined with SNR,multipath error and ionospheric delay rate.The results show that the data of BDS observations in polar stations are more affected by the elevation;the overall signal-to-noise ratio is lower than that of low latitude stations which is comparable to GPS;the multipath effect is more serious;the data from the polar stations are greatly influenced by the ionospheric activities and are different in different time periods.
    Time Series Analysis of GPS Station in Bohai Area
    QIU Yahui, BO Zhiyi, LANG Bo, YUE Caiya
    2018, 0(6):  17-21.  doi:10.13474/j.cnki.11-2246.2018.0169
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    The regional environment and climate of Bohai Rim are complex and changeable. Geology and geomorphology vary in different areas and regions. It is particularly important to explore the change rule of GPS station time series and the main noise types and spectrum law in this region. Based on accumulated data of GPS station in last years, this paper obtains the coordinate time series for each station by calculation and adjustment with GAMIT/GLOBK software, and analyzes the spectrum characteristics and periodic features using the Lomb periodogram method. At last, it studies the noise types of the station according to the linear fitting of frequency and power spectrum analysis. This article provides the theoretical basis for station time series denoising and further studies of the motion law of observation stations.
    The Extraction of Building Shadow and the Estimation of Building Heights Based on Morphology and Spectral Characteristic Parameters
    HU Yunfeng, ZHANG Qianli
    2018, 0(6):  22-26.  doi:10.13474/j.cnki.11-2246.2018.0170
    Asbtract ( )   HTML   PDF (1723KB) ( )  
    References | Related Articles | Metrics
    Building heights are important for urban landscape planning,city habitat and eco-environmental assessment.In order to solve the problem of low accuracy in the study of extracting building height by using remote sensing images and the problem of excessive human intervention,this paper uses GF-2 satellite images to realize the automatic extraction of building shadows by calculating EMSI,NDVI and land surface reflectance.And then it calculates the height of the building based on the spatial geometric relationship.Finally,the results of the study are field tested.Experimental results show that using EMSI,NDVI and land surface reflectance can effectively extract the shadow of the building,and the mean accuracy of the estimations reach 95.40%,which proves the high feasibility of GF-2 images in estimating building heights.
    Automatic Extraction of Lunar Craters Based on Neighborhood Analysis of Linear Window Using DEM
    TU Jie, ZHOU Yi, ZHAO Hao, YAN Long, WU Jinyong
    2018, 0(6):  27-33.  doi:10.13474/j.cnki.11-2246.2018.0171
    Asbtract ( )   HTML   PDF (3441KB) ( )  
    References | Related Articles | Metrics
    Craters of the moon is the most intuitive,typical geological units,so the extraction and analysis of lunar craters is of great significance to reveal the geological evolution process.This study designs neighborhood analysis of linear window for automatic extraction of lunar craters by using the 100 meters resolution DEM data derived from the Lunar reconnaissance orbiter (LRO) of America.The results of experiment by two different areas in lunar mare and lunar land show that the best extraction window of lunar mare is 1×7 and 7×1,the best extraction threshold is 4.5. The best extraction window of lunar land is 1×9 and 9×1,the best extraction threshold is 6.This method can reach 78% on the extraction rate of the craters compared to results of visual recognition.The results of evaluation factors show that the extraction accuracy of this method is more than 77%,and the extraction quality is above 70%.
    Dynamic Monitoring of Vegetation Coverage in Huainan Mining Area Based on MODIS NDVI
    WANG Guisheng, QIU Kaijian
    2018, 0(6):  34-40.  doi:10.13474/j.cnki.11-2246.2018.0172
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    The aim of this research is to analyze the evolution of vegetation cover in the Huainan mining area during the period of 2005-2014 and provide scientific references for the ecological restoration of the mining area.Based on the dimidiate pixel model and the MODIS NDVI time series products obtained every 16 days,the vegetation coverage of 2005,2008,2011 and 2014 in Huainan mining area was extracted.The temporal and spatial evolution characteristics of vegetation cover were analyzed from three aspects:temporal evolution,quantity transfer and spatial evolution.The results show that the average NDVI in the monitoring period decreased from 2005 to 2008 and increased from 2008 to 2015.The average vegetation coverage in the monitoring period was 0.722 3,0.701 7,0.718 1 and 0.702 8,respectively,with the average decrease rate of 2.7%.The area covered by the higher vegetation was the dominant vegetation cover in the study area,accounting for 50% of the total area of the study area,while the medium,low and no vegetation cover area was stable in the monitoring time,with their areas less than 200 km2,indicating the vegetation cover was generally in good condition.The transformation of vegetation cover was mainly dominated by the transformation between the relatively high coverage and high coverage.The stability condition was the main evolution direction of vegetation cover,while the alternation between mild degradation and mild improvement of vegetation were obvious.
    Fully Convolution Neural Networks for Water Extraction of Remote Sensing Images
    WANG Xue, SUI Lichun, ZHONG Mianqing, LI Dingmeng, DANG Lili
    2018, 0(6):  41-45.  doi:10.13474/j.cnki.11-2246.2018.0173
    Asbtract ( )   HTML   PDF (2288KB) ( )  
    References | Related Articles | Metrics
    This paper presented fully convolution neural networks for extracting water from remote sensing images.The paper introduced the basic principle and method of three kinds of models of fully convolution neural networks.For extracting the water target,firstly,the image data were gathered and labeled two classes——water and background.By inference and learning in fully convolution neural networks,the trained models were obtained.Finally,water target of the test images was extracted.The feasibility of the proposed models was validated by comparing the result of extraction with that of the traditional thresholding method based on image spectral features and GrabCut algorithm based on graph theory.
    Research on the Classification Method of Point Cloud Based on Elevation Difference
    MA Dongling, WANG Xiaokun, LI Guangyun
    2018, 0(6):  46-49.  doi:10.13474/j.cnki.11-2246.2018.0174
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    LiDAR point cloud data has the problem of large data volume, not easy to be recognized and difficult to deal with. In order to solve the above problems,point cloud data needs classification and processing. Aiming at the problem that the accuracy of point cloud classification is not high and the complexity of the process is complicated,a new method of point cloud classification based on height difference is proposed,which is combined with TerraSolid software.Using the method to separate the point cloud data,the first step is to deal with the original LiDAR point cloud data by TerraSolid software to remove the noise and extract the surface point cloud,and then use the second derivative of regular building and irregular vegetation height difference to extract which may be the point of the building or vegetation,and use the Gaussian deviation estimation model to provide the threshold for the classification of the building and vegetation,and finally use the breakpoint statistical model to supplement the building and vegetation point cloud.In order to prove the feasibility and effectiveness of this method,the point cloud classification of LiDAR point cloud data in Autzen_Stadium region is used.The results show that the method has the advantages of good feasibility,good sorting effect and processing automation.
    The Iterative Method of Camera Calibration
    CUI Cancan, WANG Jiali, MA Zhenling
    2018, 0(6):  50-54,60.  doi:10.13474/j.cnki.11-2246.2018.0175
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Accurate camera calibration is important for photogrammetric measurement.Traditional camera calibration methods are using the indoor/outdoor control fields and the effective camera calibration models to estimate the distortion coefficients.The various cameras have different distortions,so multi-camera calibration models are selected for calibration applications.It's desirable to find an ideal model that can be applied to most of cameras.Based on the analysis of the existing camera calibration models and methods,in this paper,a new camera calibration approach,named the iterative calibration method,is proposed.Firstly,a simple outdoor control field is established using the existing objects.Secondly,an iterative calibration method is described which applies the same or different models multiple times until the most distortions have been eliminated.Finally,combining the free network adjustment and the iterative method,camera calibration tests are carried out while no ground control points are available.Two non-metric cameras are tested and the results obtained using the traditional calibration method and iterative calibration method are analyzed.The experimental results show that the proposed camera iterative calibration method can further improve the camera calibration accuracy comparing to the traditional calibration method.
    Ground Surface Settlement Monitoring by Spaceborne InSAR Technology in Kunming
    MA Yuanyuan, CHEN Yunbo, ZUO Xiaoqing, MA Weifeng, WU Wenhao
    2018, 0(6):  55-60.  doi:10.13474/j.cnki.11-2246.2018.0176
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    In order to analyze the land subsidence in Kunming city in the period from 2014 to 2017,based on Sentinel-1 data,This paper uses SBAS-InSAR to extract ascending and descending rail mode of deformation information in Kunming city.First line of sight (LOS) converts the deformation rate on the vertical direction of the sedimentation rate.Through the ascending and descending mutual authentication and processing of observation data. it can avoid distortion of the single mode of data,inverse real land settlement,and compare with the urban historical settlement monitoring data analysis.The results show that in nearly two years during the slow settlement of Wuhua district,Kunming and relatively stable,Xishan district,north shore of Dianchi Lake in the Guandu district,and regional trends in large area subsidence and subsidence rate are faster,center for forming several sedimentation funnel,maximum rate of vertical settlement is -54.2 mm/a.
    Tunnel Cross Section Extraction and Deformation Analysis Based on Mobile Laser Scanning Technology
    DU Liming, ZHONG Ruofei, SUN Haili, ZHU Qiang, ZHANG Zhen
    2018, 0(6):  61-67.  doi:10.13474/j.cnki.11-2246.2018.0177
    Asbtract ( )   HTML   PDF (1426KB) ( )  
    References | Related Articles | Metrics
    Mobile laser scanning technology has the advantage of fast data acquisition,high density and high precision,in addition,it doesn't need to stitch the adjacent station after scanning.Based on mobile laser scanning data,the method of tunnel deformation detection and analysis is studied.Firstly,the spatial central axis of the tunnel is calculated by combining the boundary detection algorithm with random sampling consistency algorithm,and the rotation process of a large number of point clouds in traditional method is eliminated.Secondly,the k-nearest neighbor method is used to compute the buffer of each section to block the point clouds,and the sectional point sets are automatically constructed by projection method,increased the calculation speed of cross sections.Finally,an iterative elliptic fitting method is proposed to denoise the cross sections and fit the sectional curve lines.The precision of the method is verified by comparing with cross section obtained by total station.The proposed method is applied on a section of circular shield tunnel,which is intercepted into cross sections in the interval of 2 m based on the point clouds obtained by tunnel scan,and deformation analysis is performed by comparing the cross sections with theoretical one.
    A Method of Achieving Single Body for Real 3D Model Generated by Oblique Photography
    CHEN Liangchao, ZHAN Yong, WANG Junyong
    2018, 0(6):  68-72,108.  doi:10.13474/j.cnki.11-2246.2018.0178
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Achieving real 3D single model generated by oblique photography is a key technology to carry out the application of oblique photography.In this paper,a method based on the bottom texture to get real 3D single model is proposed.By acquiring the bottom information of a single object,the bottom contour texture is generated,and the bottom model is obtained,and then a RTT camera is built in the three-dimensional scene to get RTT texture of the bottom model.Finally,using projective texture mapping technology and GPU programming,the RTT texture is projected onto the 3D model of oblique photography,and the dynamic visualization of the real 3D single model is realized.Through the selection of the bottom surface model to select the real 3D single model,and then the connection of attributes and other applications based on single model are realized.Through the uniform variables provided by GPU shader language,the color modification,display and concealment of the model and operation of scene digging are realized.
    Extraction of Urban Hot Sections Based on Spatial Correlation
    LIU Jialiang, SUN Lishuang
    2018, 0(6):  73-77.  doi:10.13474/j.cnki.11-2246.2018.0179
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    The rapid increase of the amount of urban motor vehicles has brought serious traffic jams.In order to release the pressure of urban traffic,an extraction method of urban hot sections was proposed.Combining with the data of taxi track,the spatial weight matrix was set up with the rule of topological adjacency.Then the global relevance of traffic volume in various sections was analyzed.Next,the traffic hot sections were extracted based on local correlation statistics,and the distribution of traffic hot sections in different periods at workdays was analyzed.Finally,the hot section which has been extracted was simulated by using VISSIM software.The results show that the affiliation degree of the road section which needs to be verified was 0.512,which indicates that the algorithm is able to extract urban traffic hot sections effectively.
    Analysis of Atmospheric Water Vapor Content Reversion in Beijing 7·21 Rainstorm Based on GNSS
    LI Sen, JIA Guangjun
    2018, 0(6):  78-81,97.  doi:10.13474/j.cnki.11-2246.2018.0180
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    This paper introduces the principle of using GNSS observation data to retrieve atmospheric precipitable water,and analyzes the variation characteristics of atmospheric precipitation before and after 2012 Beijing rainstorm.It is found that on 21st July 2012 the precipitation in the atmosphere of Beijing was increasing rapidly in the short time.With the rainstorm weakening,the precipitation in the atmosphere was gradually reduced,and the precipitation would drop sharply after the rainstorm,and return to the normal level in the northern area.In addition,the comparison between GNSS analysis results and NECP data as well as radiosonde data demonstrates the correctness and reliability of using GNSS observation data to inverse atmospheric precipitation.
    Research on Method of D-InSAR and Level Data Fusion
    YANG Fan, ZHAO Zengpeng, ZHANG Lei, ZHANG Ziwen
    2018, 0(6):  82-85.  doi:10.13474/j.cnki.11-2246.2018.0181
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Ground subsidence is a global problem,which seriously affects the ecological environment and sustainable development.Therefore,it is very important to carry out careful monitoring and deformation prediction on the ground.According to the shortcomings of D-InSAR monitoring technology in the central area of the settlement basin,and the traditional level measurement can only get the finite element deformation information,this paper uses the ensemble Kalman filter to assimilate the D-InSAR data and the level measurement data,so that the assimilation results are more consistent with the settlement law of the subsidence area.The example shows that the results of D-InSAR and leveling data assimilation based on the ensemble Kalman filter have greatly improved the accuracy and reliability of the subsurface settlement monitoring.The average error after assimilation is 3.10 mm,which is much higher than that of D-InSAR value of 6.90 mm.
    Application of Vehicle-borne LiDAR in Urban Component Acquisition
    YUAN Debao, ZHANG Fanyuyang, LIANG Chen, HOU Xiaobo, MA Xu
    2018, 0(6):  86-90.  doi:10.13474/j.cnki.11-2246.2018.0182
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    In recent years,with the accelerating process of urbanization construction,the difficulty of urban basic management also increases.As an important measure in the process of urban informatization development,digital city management project plays a significant role in improving the level of urban management.Vehicle-borne LiDAR measurement technology is relatively mature in China,and it can improve the capabilities of city component data acquisition.This paper studied the application of vehicle-borne LiDAR in urban component acquisition.By comparing with the traditional CORS measurement data,the technical process and the accuracy of point cloud data were analyzed in detail,which provided a new method for the acquisition of urban components in digital urban management.
    Land Use Dynamic Monitoring of Fengyang Quartz Mine Area Based on Landsat Images
    ZHANG Wei, WU Yanmin, LIU Jikai
    2018, 0(6):  91-97.  doi:10.13474/j.cnki.11-2246.2018.0183
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    The land use information and its change characteristics are studied based on RS and GIS methods of quartz mine area in Fengyang county from 1991 to 2015.The results show that:①Our Landsat satellite image classification algorithm based on SVM is efficient and acquire high classification accuracy for overall accuracy and Kappa coefficient,reaching 94.78% and 0.934 0,respectively.②Significant changes in both land use ways and temporal-spatial pattern have taken place in Fengyang county during the past 25 years.The quartz mine area undergoes a trend of dramatic increase with the fastest speed,from which most of areas are converted from grassland and forestland.The urban construction land increases continuously,from which most of areas are transformed from farmland,grassland and water.The water first decreases and then increases with a lower decreasing ratio.The grassland decreases rapidly with the maximum variation,most of which are converted into forestland,farmland and quartz mine area.The forestland increases 624.33 hm2.The farmland which distributes in villages rivers around decreases due to desertification or occupation by the construction land expansion.③The land ecosystem has been deteriorated to a dangerous level over the past 25 years.More specifically,the areas of quartz mine and urban land construction have been both increased significantly.On the contrary,the vegetation and the water regions have been decreased year after year.
    Study on the Construction of Ecological Environment Evaluation Index System of Ningbo City Based on Geographical Condition Monitoring
    XIANG Zhiyong, ZOU Xiaoling, CHEN Jiangping
    2018, 0(6):  98-103.  doi:10.13474/j.cnki.11-2246.2018.0184
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Based on the characteristics of geographic national conditions monitoring data and the needs of ecological environment evaluation,combining the pressure-state-response model,this paper puts forward the index system of ecological environment evaluation of Ningbo.This paper uses the geographic national conditions monitoring data of Ningbo to carry out the index calculation result.The results show that the index system proposed in this paper can well evaluate the ecological environment of Ningbo city,which is in accordance with the actual situation of Ningbo city.
    Analysis of Large Scale Mapping Capability of Consumer Unmanned Aerial Vehicles
    WAN Jianhua, WANG Zhao, LIU Shanwei, FENG Jianwei, LIU Rutao
    2018, 0(6):  104-108.  doi:10.13474/j.cnki.11-2246.2018.0185
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    With the advance of consumer-level unmanned aerial vehicles (UAVs) technology,it is possible to conduct photogrammetry by using consumer-level multi-rotor UAVs.In the paper,the unmanned aerial vehicles are first equipped with the ordinary high-precisely calibrated camera.Then the characteristics of the consumer-level UAVs is used to design and analyze the deployment of photo-control point,which can generate the general law of the deployment of photo-control point for consumer-level UAVs photogrammetry.The ability of performing large-scale map is analyzed and evaluated for UAVs.This result indicates that the mapping accuracies of UAVs,including aerial triangulation,the resolution and the elevation,meet the precise requirement of large-scale terrain survey,involving 1:500,1:1000 and 1:2000.Using consumer-level UAVs to conduct large-scale survey can improve the efficiency of work,reduce costs and be applied to mapping small area.
    An Algorithm of Historical Aerial Image Registration Based on Aerial Photograph
    SUN Haiping, ZHANG Jingyi, YANG Zedong, LIU Jie
    2018, 0(6):  109-113.  doi:10.13474/j.cnki.11-2246.2018.0186
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Historical aerial images objectively reflect the surface morphology,vegetation cover and environmental conditions,and objectively reserve the evolution of natural and human landscapes.In order to efficiently manage and effectively use these valuable historical aerial images,it is imperative to establish an historical aerial image database.Currently,many avionics database management systems have done a good job in the management of aerial photography data,and can browse and update a single image data at the same time,but they can not realize spatial inquiring and roaming of historical aerial images.In this paper,using historical aerial photograph data,based on digital image processing and digital photogrammetry theoretical methods,authors designe the semi-automatic aerial image without control points stitching algorithm,and realize the mass rapid stitching of aerial images.Finally,according to accuracy testing for the stitching overlay images and vector data,the main landmarks overlapped well and the query results meet the precision requirements.
    Combining Point Cloud Data and BIM Technology for 3D Reconstruction and Informational Management of Ancient Buildings
    WANG Lingwen
    2018, 0(6):  114-117,129.  doi:10.13474/j.cnki.11-2246.2018.0187
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    This paper puts forward a comprehensive modeling method for ancient buildings based on scanning point cloud.For irregular or complex parts,triangular mesh models are constructed by Delaunay triangulation.On the contrary,for relatively simple and organized features,the entity models are directly built under the reference of the point cloud.With the advantages of the BIM,informational management of the models of ancient buildings are realized.Experiments show that the proposed 3D reconstruction method for ancient buildings can reconstruct a detailed model with smaller data,and the informational management method can provide sustainable and efficient management of ancient buildings' geometry and attribute information in stages.
    Study on the Settlement Prediction Model of Richards Curve Optimized by Markov Chain
    ZHAO Yahong, HE Liming, WANG Jinxing, HAO Yanjin, NIU Qintao
    2018, 0(6):  118-121,134.  doi:10.13474/j.cnki.11-2246.2018.0188
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Aiming at the nonlinear and random characteristics of building settlement,a Richards curve prediction model based on Markov chain correction was established to improve the prediction accuracy of the model.First,the fminsearch function of Matlab platform was used to obtain the optimal parameter solution of Richards model,based on the principle of minimizing the sum of squared error between the fitted value and the measured value.Then,the residual error was corrected by Markov's method,finally the combination model was used to predict the settlement.The prediction accuracy of the model was compared and analyzed by examples.The results show that it was effective to estimate the Richards parameters by using fminsearch.The average absolute percentage error and the root mean square error of the Richards model optimized by Markov chain were smaller than the single model prediction,and the prediction accuracy was improved.The combined model prediction results can be better reflect the overall trends of data series development and changes over time as well as the inherent laws between the various states of the system,and it is suitable for building settlement prediction.
    Application of Improved SVR in Prediction of Side Slope Displacement of the Dam
    LIU Xiaosheng, YU Liang
    2018, 0(6):  122-125.  doi:10.13474/j.cnki.11-2246.2018.0189
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Aiming at the problem of low prediction accuracy for side slope displacement of the dam caused by the insufficient of parameters optimization of traditional support vector machine (SVM),this paper proposed an improved grid parameter optimization method,which required to conduct a coarse search first,followed by several times of fine search.Based on the improved grid parameter optimization method,we established a prediction model for side slope displacement of SVR dam,and applied it in the prediction of side slope displacement.The results showed that the prediction model,established based on the improved method for predicting side slope displacement of SVR dam,had better prediction accuracy than the prediction model basing on traditional SVM.
    A Method for Evaluating the Precision of 3D Control Network
    ZHANG Yifei, JIN Limin, FAN Yichen, ZHU Wanqian
    2018, 0(6):  126-129.  doi:10.13474/j.cnki.11-2246.2018.0190
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    According to the layout of synchrotron facility and beamline,a new method is proposed to evaluate the control network precision,which is based on the reference points' the straightness and deviation.An experiment model is constructed to simulate the transfer station measurement process of beamline control network.Close-loop measuring can reduce the deviation effectively.While transferring a beamline control network at SSRF,deviation of control network was accurately judged by reference points' deviation.
    A Web Publishing Solution of Geospatial Information Based on Mapserver and OpenLayers
    LU Yongguang
    2018, 0(6):  130-134.  doi:10.13474/j.cnki.11-2246.2018.0191
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Since the advent of WebGIS,with the promotion of computer technology and Internet technology,it has achieved rapid development.Various commencial and open source software have been developed,providing a variety of WebGIS solutions.The paper discusses a web publishing solution of geospatial information based on Mapserver and OpenLayers,including specification of geospatial data and configuration of Mapfile.It also gives some optimization suggestions,which can offer a reference for the readers.
    Design and Implementation of Power Tunnel Structure Safety Monitoring System Based on Optical Fiber Sensing Technology
    LI Weihai, CHEN Lijia
    2018, 0(6):  135-138,152.  doi:10.13474/j.cnki.11-2246.2018.0192
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Urban power tunnel has many characteristics,such as diverse structure,small section size,many facilities,large electromagnetic interference and so on.During operation,it is time-consuming and laborious to use traditional measurement method for deformation monitoring,and it is difficult to ensure monitoring accuracy,intelligent monitoring is needed.The application of optical fiber sensing technology has gradually become a new trend in the application of the industry,but the application of optical fiber sensing technology in the deformation monitoring of small section tunnel is rarely seen.In this paper,the design and development of power tunnel automation optical fiber sensing technology of deformation monitoring system based on the results of application show that the system realizes wireless transmission,automation,high precision,real-time data acquisition,analysis and early warning function,which greatly improves the work efficiency,reduce the cost of operation and maintenance,for other similar deformation monitoring with a high demand for application and reference value.
    The Underground Pipeline Information's Construction and Administration under the Background of Co-construction and Sharing of Urban Fundamental Information
    XU Danyan, LIU Ying, YAN Jianguo, LIU Xiangnan
    2018, 0(6):  139-143.  doi:10.13474/j.cnki.11-2246.2018.0193
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Underground pipeline information is the fundamental demand to ensure urban planning,construction and administration,it's also the important basis of professional pipelines' operation and management.How to strengthen the underground pipeline information's co-construction and sharing has been a hotspot issue during the current Smart City progress in China.This paper analyzes the main problems faced by the urban underground pipelines' information administration from administration system,standard and regulation,information sharing,information undate and legislation construction.Then this paper discusses the main measures and ongoing challenges confronted by underground pipeline information's co-construction and sharing.On this basis,the paper puts forward some suggestions about improving legal system,optimizing organization structure,strengthening special planning,promoting the construction of One Map,application and research and development of new technologies, etc.
    Reforming and Practicing of Surveying and Mapping Engineering Talent Training Model under the New Situation
    LIU Xiaoyang, LI Feng, SUN Guangtong, SONG Ping, LIU Jun, WANG Qiuling, QIAN An
    2018, 0(6):  144-147,152.  doi:10.13474/j.cnki.11-2246.2018.0194
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Based on the background of engineering practice ability training and innovation education,the paper analyzes the present situation and shortcomings of personnel training of surveying and mapping engineering.Combined with the surveying and mapping engineering of Institute of Disaster Prevention,the paper explores and practicates the reform of training program,practice teaching system,teaching method and examination method et al,providing some reference for talent development of advanced training talents with innovative spirit.
    Comparison of GNSS Data Quality Check Tool TEQC and SpiderQC
    WANG Kaifeng, WANG Yong
    2018, 0(6):  148-152.  doi:10.13474/j.cnki.11-2246.2018.0195
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    In the operation and maintenance of JSCORS,a large number of GNSS data quality inspections are involved.This article describes some statistical indicators of Jiangsu CORS in the process of data quality inspection,as well as the tools TEQC and Leica SpiderQC used to implement these quality checks.Through comparison and demonstration of the features of the two softwares,they provide reference for the selection of tools in similar work.
    Application of 3D Laser Scanning Technology in Assembly Line Construction
    JING Weili
    2018, 0(6):  153-155.  doi:10.13474/j.cnki.11-2246.2018.0196
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    Powerline construction is a very important part in the power transmission and transformation project.The traditional method is through the arc-sag,but the efficiency is very low and cannot be widely used when passing across high-speed or high-speed railways.This requires using of prefabricated wire-laying technology.The total station instrument with the prism measurement method was proved,but there are also hidden dangers.This article combines the actual project,focus on the application of three-dimensional laser scanning technology in the assembly powerline construction.
    Application of UAV Image Matching Point Cloud Technology in Road Survey
    LI Tao, YUAN Zhongchao, SHEN Biaoqun, GAO Bo, WANG Shengxin
    2018, 0(6):  156-159.  doi:10.13474/j.cnki.11-2246.2018.0197
    Asbtract ( )   HTML  
    References | Related Articles | Metrics
    With the progress of technology and the accumulation of experience,the application of UAV aerial survey has been expanding,and point cloud has gradually become a new type of surveying and mapping geographic information product.The application of point cloud can greatly improve work efficiency and reduce labor intensity in the field.Sirius UAV as a high precision measuring UAV,the image matching point cloud can make a high precision digital elevation model,which can be used for the calculation of the earthwork of the road and the design of any section.Taking a highway road surveying project as an example,through the contrast analysis,this paper elaborates the feasibility of the application of new technology,which can provide a reference for similar projects.