Table of Content

25 April 2022, Volume 0 Issue 4

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An ultra wide band indoor positioning method considering electrical delay

ZHAO Yinzhi, ZOU Jingui, CAI Lixian, HUANG Gege

2022, 0(4):  1-5,31.  doi:10.13474/j.cnki.11-2246.2022.0100

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Aiming at the problem that many kinds of errors affect the positioning accuracy in UWB positioning system, the errors of UWB indoor positioning are comprehensively analyzed, and the basic function model of UWB indoor positioning is proposed in this paper. The system difference of "electrical delay" and three-dimensional coordinates are regarded as estimated parameters, and the positioning results are obtained by Gauss-Newton iterative algorithm. The experimental results show that the proposed method can effectively eliminate the system deviation. Coordinates measured by the total station are taken as true values in the static experiments, and the positioning errors are 4.1 and 2.3 cm, respectively, which are 64% and 87% higher than that of the existing methods. The dynamic experiment results are closer to the reference trajectory and the maximum error is less than 10 cm.

Registration and seamless fusion of point cloud from LiDAR and oblique photography

RUAN Minghao, LU Yonghua, LIU Yuxian, TANG Shengjun, WANG Weixi, ZHANG Yuqi, LI You

2022, 0(4):  6-10.  doi:10.13474/j.cnki.11-2246.2022.0101

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The traditional and widely used urban space modeling methods such as laser point cloud and oblique photography have their own advantages and disadvantages. How to effectively integrate data from different sources and use them in the construction of city 3D models is the current difficulty in city modeling. Therefore, this paper proposes a precise registration and seamless fusion method for laser and oblique point clouds. This method can overcome the inconsistency of scale and accuracy of point cloud data from different sources, accurately calculate the spatial transformation relationship of data from different sources, and on this basis, data redundancy is eliminated, and the seamless integration of multi-source point cloud data is completed. Finally, this paper uses the data obtained in three sets of actual scenes to verify the effectiveness and accuracy of the elimination method in this paper. The experimental results show that the fusion data obtained by this method has better completeness and data accuracy than the single platform data.

Research on the early warning and simulation of land space planning in mountainous city from the perspective of new surveying and mapping

HE Yuqi, ZENG Yixiao, CHEN Guang, CHEN Liangchao

2022, 0(4):  11-15.  doi:10.13474/j.cnki.11-2246.2022.0102

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Facing the fundamental positioning of supporting the "two unifications" of Ministry of National Resources and the "two supports and one lift" of basic surveying and mapping, the industry is gradually focusing on applications and services. From the perspective of the new intelligent transformation of surveying and mapping, and addressing the problems on diversity of early warning indicators and complexity of scenario construction in urban scale planning, this paper aims at the implementation and supervision of land space planning, explores a set of early warning and simulation framework, carries out an application demonstration of dynamic water level simulation in typical areas, serves the follow-up links of planning preparation and dynamic maintenance, and helps land space planning form a closed-loop management.

Research on construction and demolition waste stacking point identification based on DeeplabV3+

LIU Xiaoyu, LIU Yang, DU Mingyi, ZHANG Min, JIA Jingjue, YANG Heng

2022, 0(4):  16-19,43.  doi:10.13474/j.cnki.11-2246.2022.0103

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It is difficult to identify the location, type, area and volume of construction waste piled up illegally in remote sensing images quickly, accurately and effectively. In this paper, based on convolution model, the multi-spectral remote sensing image and panchromatic remote sensing image on its NNDiffuse pan sharpening algorithm fusion processing, it improves the precision of image resolution, in-depth analysis the characteristics of the construction waste pile up some information in remote sensing image. Use DeeplabV3+ network model and the encoder to target the shallow features and high-level semantic feature. From the perspective of image sample data balance adjust the sample weight coefficient to further improve the identification accuracy. Experimental results show that the identification accuracy of construction waste dumps using DeeplabV3+ network reach 82%, which is beneficial to realize the dynamic monitoring and management of construction waste.

Deformation monitoring and mechanism analysis of urban subway line based on PS-InSAR technology

LI Jiahao, ZHOU Lü, MA Jun, YANG Fei, XIAN Lingxiao

2022, 0(4):  20-25.  doi:10.13474/j.cnki.11-2246.2022.0104

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This paper uses PS-InSAR technology to obtain information on the field of subsidence rate and accumulated subsidence in the Shanghai area, and analyzes the temporal and spatial distribution characteristics of subsidence in this area, as well as the correlation between subsidence and precipitation in this area, subway construction and operation and other influencing factors. The research shows that:①The subsidence in Shanghai is unevenly distributed. The subsidence in the north of Shanghai is relatively stable, while the Hongkou district in the middle, the Minhang district in the south, and the Pudong new area in the east all have different degrees of subsidence. Among them, the Minhang district has the most serious subsidence, and the maximum cumulative subsidence is -43 mm, with large-scale, large-scale subsidence. ②The subsidence in the study area is nonlinear. The apparent seasonal change of subsidence is related to regional precipitation. The timely supplement of rainfall to groundwater can effectively alleviate excessive groundwater. ③Some sections of Line 3, 15 and 16 of Shanghai subway all have obvious settlement, and the settlement of Line 15 in the construction stage is the most obvious, and the maximum accumulated settlement of some sections is -34 mm.

Multi-task automatic identification of loess landslide based on one-stage instance segmentation network

SHI Yun, SHI Longlong, NIU Minjie, ZHAO Kan

2022, 0(4):  26-31.  doi:10.13474/j.cnki.11-2246.2022.0105

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Automatic landslide identification can solve the problem of slow speed of manual visual interpretation. The existing automatic identification methods based on deep learning are mainly single-task recognition methods such as object detection and semantic segmentation.In this paper, the instance segmentation network based on deep learning is used to explore a multi-task identification method that can achieve landslide target location and semantic segmentation simultaneously.Firstly, a dataset of 3822 loess landslide samples is constructed based on Google Earth images. Then,the multi-task automatic identification model of loess landslide based on small sample learning is constructed by using the one-stage instance segmentation network YOLACT. Finally, the identification results are evaluated by the large, medium and small scale landslide test samples. The results show as follows:①The average precision of landslide target positioning Box is 61.66%, the average precision of landslide semantic segmentation Mask is 62.0%, and the intersection over union of Mask in large scale test is 0.88. ②The landslide identification model built based on YOLACT can complete the dual-task identification of landslide target positioning and high-precision mask segmentation at the same time, which proride technical support for the automatic multi-task identification and rapid mapping of landslide.

Hyperspectral image classification based on multi-feature fusion and dimensionality reduction algorithms

DOU Shiqing, CHEN Zhiyu, XU Yong, ZHENG Hegang, MIAO Linlin, SONG Yingying

2022, 0(4):  32-36,50.  doi:10.13474/j.cnki.11-2246.2022.0106

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Hyperspectral images does exist redundant information, which brings certain side-effects on image classification. In this study, two dimensionality reduction algorithms, the CB method (CfsSubsetEval evaluator combines Best-First search strategies) and the PCA, and four multi-feature fusion combinations are proposed to construct eight schemes. The eight schemes combining with RF(random forest) classifier are then applied to classily hyperspectral images, and the best scheme for hyperspectral image classification are selected on the bases of the classification accuracy and Kappa coefficient. The results show that:①Multi-feature fusion can improve the classification accuracy of hyperspectral images, the classification accuracy of the hyperspectral image increases with considering geographic characteristics, texture characteristics, and exponential features gradually both in the two dimensionality reduction algorithms.②Considering the two dimensionality reduction algorithms, the classification accuracy based on CB reduction is generally higher than that of PCA dimensionality reduction. In terms of the classification accuracy based on eight schemes, the CB method with spectrum information, geographic characteristics, texture characteristics, and exponential features has the highest classification accuracy with 98.01% of overall classification accuracy, and 0.969 9 of Kappa coefficient.

Automatic power line extraction algorithm for aerial image under complex background

CHEN Zhu'an, ZOU Zilong, XU Zhifang, PENG Jiaqi, SHI Chenjing, HONG Zhiqiang

2022, 0(4):  37-43.  doi:10.13474/j.cnki.11-2246.2022.0107

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The key problem of UAV power line inspection is how to accurately extract power lines from aerial images with complex background. This paper proposes a new algorithm for power line extraction based on two-dimensional variational mode decomposition (2D-VMD). Firstly, the original aerial image is preprocessed to speed up data processing. Secondly, 2D-VMD algorithm is utilized to decompose the preprocessed image. The IMF component graph with power line features is selected by the improved point sharpness algorithm and edge detection is performed by Roberts operator. Finally, the power lines are extracted by morphological modification of Hough transform. Experimental results show that the proposed method is more accurate, noise resistant and automatic than the traditional Canny edge detection combined with Hough transform method, line segment detector (LSD) method, Roberts edge detection and morphological improved Hough transform method.

A simplification method for 3D model of oblique photography considering geographic categories

LAN Feng, ZHANG Fan, GAO Yunlong, HUANG Xianfeng

2022, 0(4):  44-50.  doi:10.13474/j.cnki.11-2246.2022.0108

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3D modeling based on oblique photogrammetry has become the development trend of 3D urban construction. The vegetations with uneven surface need a large number of triangles to depict in the urban model, but this is not the focus of 3D real scene data recording and expression, it is difficult to display and apply the model due to a large amount of data. So, this paper proposes a 3D model simplification method of oblique photography considering the types of ground objects. Firstly, vegetation area is extracted by using Markov random field (MRF) based on textural and geometric information. Then, the quadric error metrics (QEM) algorithm is used to simplify the vegetation area. Finally, the texture remap of the simplified white film model is performed. The experimental result shows that the method in this paper can extract and simplify the vegetation area effectively, the texture remap result is almost the same as the original model in appearance. The method proposed in this paper has achieved the desired result.

Landslide identification in Jinsha River basin based on high-resolution remote sensing:taking Wangdalong village of Batang county as an example

DING Yonghui, ZHANG Qing, YANG Chengsheng, WANG Meng, DING Hui

2022, 0(4):  51-55.  doi:10.13474/j.cnki.11-2246.2022.0109

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Because of the steep terrain,the development of soft rock,and the concentration of rainfall on both sides of the Jinsha River basin,the landslide disasters are densely distributed in the basin.High-resolution remote sensing is an important means of landslide identification,but the visual interpretation method for large-scale landslide hazard identification has the characteristics of heavy workload and low efficiency.In this paper,the object-oriented classification method is used to identify the large-scale landslides in Jinsha River basin.The spectrum,shape and space characteristics of landslides are used to identify the landslides in the region.At the same time,the Wangdalong village section of Batang county in the Jinsha River basin is selected for the identification and extraction of landslides.In this area,18 landslides are identified by object-oriented classification method,12 of which are the same as the results of visual interpretation,and the consistency is 75%.In addition,3 hidden landslides are found which are not identified by visual interpretation.The results show that the recognition effect of this method is good,which can provide a reference for the subsequent large-scale landslide identification extraction and landslide cataloging work in the Jinsha River basin and even along the Sichuan-Tibet railway.

Extraction of rocky desertification information using NDVI-Albedo feature space

LUO Jie, LIU Suihua, RUAN Ou, HU Haitao

2022, 0(4):  56-60,82.  doi:10.13474/j.cnki.11-2246.2022.0110

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Rocky desertification is one of the most crucial ecological and environmental problems in the karst area of Southwest China. Monitoring rocky desertification is an important task for the prevention and control of rocky desertification. Taking a typical rocky desertification research area of Dougu town in western Weining as an example, based on Landsat8 OLI remote sensing data, the normalized vegetation index(NDVI) and Albedo of the research area are calculated, and the rocky desertification difference index (RSDDI) is constructed through the NDVI-Albedo feature space to extract the rocky desertification information and verify its accuracy. Studies have shown that the rocky desertification difference index constructed based on the NDVI-Albedo feature space method can extract and classify rocky desertification information more accurately and conveniently, and the accuracy of the mapping for moderate rocky desertification and severe rocky desertification is both reaching more than 89%, the extraction effect is excellent, which is conducive to the quantitative assessment and monitoring of rocky desertification in the southwest of China karst area.

Rural buildings extraction based on deep learning model with dilated convolution and pyramid representation

WANG Xue, LIANG Ke, SUI Lichun, ZHONG Mianqing, ZHU Jianfeng

2022, 0(4):  61-65.  doi:10.13474/j.cnki.11-2246.2022.0111

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Automatic extraction rural buildings faces many difficulties because of the diverse structure and complex spatial distribution, etc. Aiming at this problem, this paper proposes a neural network model with dilated convolution and pyramid representation for automatic extracting rural buildings in remote sensing images. In the dilated convolution neural network module, the feature information with different receptive fields is obtained by changing the size of the dilated hole. In the pyramid representation, each module inputs different scale information, and the rate of down sampling is also different, which obtains multi-dimensional pyramid scale features. Finally, the model is fused shallow feature and deep feature to construct improved deep learning model for rural building automatic extraction. Compared with FCN-8s and DeepLab models, the experiment results show that this method performs better in the extraction of rural buildings. The accuracy of the extraction is obviously improved, the boundary details are better retention and the noise is little.

Study on extraction impervious area of urban based on Sentinel+ Landsat image

XIAO Bin, ZHOU Zhonggan, FAN Junlin, XU Kan, LIU Xiangtong

2022, 0(4):  66-71,95.  doi:10.13474/j.cnki.11-2246.2022.0112

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Impervious surface is one of the important indexes to measure the development degree of urbanization and evaluate the quality of urban ecological environment. Nanchang is one of the typical regional cities of Poyang Lake eco economic circle. It is of great significance to obtain the impervious surface information accurately, timely and efficiently for Nanchang to provide a new decision-making reference for its economic development and ecological planning. Most of the existing researches on impervious surface are focused on extracting impervious surface information from single optical remote sensing image data. However, due to the influence of image data sources, the classification results often have spectral confusion and "salt and pepper" phenomenon, which limits the further improvement of impervious surface classification accuracy. In order to improve this situation, this study takes Nanchang city as the research area, comprehensively considers the advantages of multi-source remote sensing image data, and explores the applicability, advantages and disadvantages of impervious surface information extraction based on Sentinel+Landsat image.

Obtaining high-precision digital elevation model in Antarctica based on TanDEM-X images and ICESat-2 data

LIU Zhuo, LI Jia, ZHANG Xiang, GUO Lei, LIU Yanyang, XU Haodong, GU Yunyang, CHEN Chonghua

2022, 0(4):  72-76.  doi:10.13474/j.cnki.11-2246.2022.0113

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High-precision digital elevation model (DEM) is one of the basic geographic information data required for Antarctica scientific research. The TanDEM-X bistatic SAR pairs released by the German Space Agency has the advantages of high-resolution and wide coverage. More importantly, it has a zero temporal baseline, which makes them to be free of time decorrelation, atmospheric variation, and ground deformation. In this paper, we firstly use TanDEM-X images and the iterative differential InSAR technology to obtain high-resolution Antarctic DEM,and then improve the accuracy of the DEM products by correcting the horizontal shift based on the ICESat-2 data and least squares adjustment technology. The research results show that the method can obtain Antarctica DEM with resolution higher than 5 m and absolute precision better than 2 m.

Spatial-temporal characteristics and driving forces of the cropland in rocky desertification area from 1990 to 2019:taking Fuyuan county as an example

WANG Limeng, WANG Jiasheng, YANG Kun, WANG Zhimin, SU Fanjie, CHEN Xinya

2022, 0(4):  77-82.  doi:10.13474/j.cnki.11-2246.2022.0114

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Aiming at the problem of limited time and space scale in the study of cropland change in rocky desertification area, this paper takes Fuyuan county as an example, based on Landsat remote sensing data from 1990, 2000, 2010, and 2019, uses the classification method of multi-feature and random forest to extract cropland, uses cropland coverage, cropland type conversion and slope zonal statistics to analyze the characteristics of the spatial-temporal cropland change in the past 30 years (1990-2019), and discusses the driving forces for cropland change. The results show that the cropland area in Fuyuan county increased firstly (1990-2010) and then decreased (2010-2019). The main sources and transformation types of cropland area are woodland and grassland, with woodland being the most. It is mainly distributed in five towns with less rocky desertification area in the north, and mainly in the gentle slope area. The cropland coverage show a process from low to high to low, and the cropland change rate in the steep slope area vary significantly in different periods. The cropland change in Fuyuan county has been formed by the combined effects of population, economic, policy, and transportation factors under the unique geographical environment of rocky desertification area in the past 30 years. The conclusions of this paper can provide data support for the assessment of ecological security and food security in rocky desertification area.

UAV route planning and 3D modeling analysis in different terrain environment

BI Rui, GAN Shu, YUAN Xiping, LI Raobo, GAO Sha

2022, 0(4):  83-89,129.  doi:10.13474/j.cnki.11-2246.2022.0115

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Aiming at the problems of low flight safety, data redundancy, and poor quality and accuracy of constructing 3D models in different terrain environments. This paper uses single-lens quad-rotor small UAV as the experimental equipment. To the complex single building in flat terrain environments uses tic-tac-toe cross routes and circumferential routes. To the mudslide gully in complex mountain terrain environments uses horizontal routes, tic-tac-toe crossing routes, and video routes to construct the 3D model. Combined with route parameters, 3D model quality accuracy, the influence of the UAV route planning scheme on 3D model construction under different terrain environments is discussed. As indicated by the results, used the circumferential route could safely and quickly acquire images of complex single building in flat terrain, and construct a complete, good quality, and accurate 3D model.Used the tic-tac-toe cross routes can construct a complete, good quality, and accurate 3D model of the mudslide gully in mountainous terrain, but the flight safety and timeliness are low. Used the video routes, the image overlap is high, and a complete, high-quality 3D model can be constructed, the accuracy of the model is not significantly different.

Integrated navigation algorithm of multi-joint deep-sea vehicle

WAN Yingneng, XU Xuehan, LIU Kexian

2022, 0(4):  90-95.  doi:10.13474/j.cnki.11-2246.2022.0116

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To solve the positioning problem of a multi-joint underwater vehicle, a integrated navigation algorithm based on strapdown inertial navigation+dead reckoning is proposed in this paper. The method measures the position of vehicle by the strapdown inertial navigation, and gets the position of the vehicle at the next moment by the dead reckoning, and the measured information is processed by Kalman filter to get the high accuracy position information. The performance of other two single navigations systems are studied comparatively on MATLAB/SIMULINK platform. The simulation results show that the position error can be controlled within 5 m when using the integrated navigation algorithm, which can meet the positioning requirements of the multi-joint underwater vehicle.

Multi-source POI matching method based on multi-feature similarity

LUO Guowei, YE Jiayuan, WANG Jinfeng

2022, 0(4):  96-100.  doi:10.13474/j.cnki.11-2246.2022.0117

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Aiming at the problem that multi-source POI feature differences lead to the difficulty of identifying the same objects, this paper proposes a multi-source POI matching based on feature similarity method. Considering POI spatial and non-spatial attributes, four features including name, location, address and classification are selected for similarity calculation. The importance of each feature index is analyzed by analytic hierarchy process, and the feature weight information is obtained. The candidate matching objects are screened according to the total similarity to determine the final matching comparison. Experimental results show that the proposed method has high matching accuracy and is more suitable for multi-source heterogeneous POI data matching. It can meet the demand of efficient matching of multi-source POI data.

Measurement of coupling and coordination of socio-economic and ecological environment in rural villages of the Yellow River basin and analysis of influencing factors

YAN Mingtao, QIAO Jiajun, QU Meng, ZHU Qiankun, HAN Dong

2022, 0(4):  101-105,116.  doi:10.13474/j.cnki.11-2246.2022.0118

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Based on the panel data of 136 districts and counties in the Yellow River basin in 2008, 2010, 2012 and 2014, the coupling coordination level and influencing factors are analyzed using entropy TOPSIS analysis, coupling coordination degree model and geographic probe model. The results show that:① The trend of coupling coordination between socio-economic development and ecological environment quality in the Yellow River basin during the study period is in a "U" shape curve, and is generally in a highly coupled low-level coordination stage. The trend of inter-regional variation is an inverted "U" curve. From the relative development model, the quality of rural ecological environment lags behind from 2010 to 2014. ② The spatial pattern is characterized by significant spatial divergence, and the distribution pattern of coupling coordination is "upstream > midstream > downstream". ③ Natural environmental factors are the dominant factors influencing the spatial divergence of coupled coordination, followed by socioeconomic factors. Among them, rural population density, annual average PM_2.5 concentration, per capita arable land area, topographic relief, elevation and annual average temperature are the main factors, and the interaction of the two factors is significantly greater than the influence of a single factor. Based on this, it is suggested that the Yellow River basin should be guided by the concept of coordinated development, focusing on improving the protection and restoration of ecological environment and adopting differentiated and characteristic development strategies, with a view to achieving ecological protection and high-quality development in the Yellow River basin at an early date.

Analysis of the site selection evaluation system for rural leisure and pension projects

ZHANG Puwei, FU Liang, WANG Guohua, LU Yannan, ZHAO Haiyun

2022, 0(4):  106-110.  doi:10.13474/j.cnki.11-2246.2022.0119

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In response to the difficulty of siting decisions for rural leisure and pension projects, methods such as literature research, expert panels, and questionnaire surveys have been applied to construct a "4 levels, 2 dimensions, 5 elements and 12 indicators" rural leisure and pension project site selection evaluation index system, determine the weight of each level of indicators, and determine scoring rules for 12 indicators. According to the constructed evaluation system, combined with GIS software tools, an empirical evaluation of Zhongyuan township, Jing'an county, Jiangxi province, a typical rural area for the developing leisure and pension industry, was carried out, and the results verified the effectiveness of the evaluation system. The evaluation system can be used to guide the site selection practices of other similar rural leisure and pension projects, ensuring the efficient use of rural land resources and the high-quality development of the rural leisure and pension industry.

Application research of BDS precise point positioning on dynamic positioning system of offshore oil drilling rig

LUO Youan, JIANG Aiguo, YANG Fuxin, ZHANG Jie, HE Dongxu, XU Yinglong

2022, 0(4):  111-116.  doi:10.13474/j.cnki.11-2246.2022.0120

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The dynamic positioning (DP) offshore drilling rig depends on the high precision position reference datum. Precise point positioning (PPP) technology based on global navigation satellite system is the best choice to provide ocean high precise position service. At present, the high-precision position reference datum of offshore drilling rig mainly depends on GPS. With the completion of BeiDou Navigation Satellite System (BDS), the BDS real-time PPP will provide independent and high-precision position reference in the global ocean. In this paper, a self-developed receiver based on BDS real-time PPP is carried out and connected to a DP system in the South China Sea. The results show that compared with similar GPS receiver, the three-dimensional position difference after convergence is less than 50 cm. Meanwhile, the weight of BDS and GPS information is the same in Kongsberg DP system. It verifies the feasibility of DP offshore drilling rig operation based on single BDS position reference datum.

Real-time precise point positioning precision analysis based on PPP-B2b service

XIAO Haowei, WANG Jianglin, GUO Hairong, YANG Liyang

2022, 0(4):  117-121.  doi:10.13474/j.cnki.11-2246.2022.0121

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Based on the officially released PPP-B2b signal by BeiDou, which carries the precise point positioning(PPP), and the latest high-precision positioning terminal developed by South Surveying & Mapping Technology Co., Ltd.(SOUTH), this article utilizes observation data and real-time positioning results of 6 cities across the country for a week to analyzes the accuracy of the PPP results based on PPP-B2b service. In this paper, the focus is on analyzing the accuracy of real-time static PPP and real-time dynamic PPP positioning. Experimental results show that the static PPP positioning accuracy based on the PPP-B2b service is better than 7 cm in the horizontal direction, and better than 10 cm in the vertical direction; the dynamic PPP positioning accuracy based on the PPP-B2b service is better than 10 cm in the horizontal direction, and better than 15 cm in the vertical direction. A conclusion can be made that the precise point positioning based on PPP-B2b service can reach centimeter level in static mode and decimeter level in dynamic mode.

Deformation monitoring of bridge structure in mining area using 3D laser scanning technology

ZHANG Chi, BAI Zhihui, LI Liang, CHEN Ranli, WU Kan

2022, 0(4):  122-129.  doi:10.13474/j.cnki.11-2246.2022.0122

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The point cloud data of buildings measured by 3D laser scanning technology can clearly represent the three-dimensional spatial information of buildings, and provide high-precision and high-density surface description of buildings. The point cloud itself does not directly display its own characteristic information, so when extracting local deformation, point cloud segmentation is needed. Most of the existing segmentation algorithms applied to buildings and structures rely on the characteristics of them to set the mutation threshold. When encountering complex scenarios, these assumptions often lead to errors. With the extension of machine learning in the field of point cloud processing, a new idea has emerged in the recognition of buildings and structures' boundaries and point cloud data segmentation. Taking the 3D laser scanning data of two phases of a railway bridge above the working face of a mining area as an example, this paper uses the neural network method to segment and extract the steel structure of bridge arches. After training 10 million marked bridge points, the neural network model can learn operators to recognize the attributes of points in the point cloud and mark them, then extract the steel structure point cloud in the two phases of data. In the next way, this paper analyzes the point cloud of steel structure of bridge arches segmented by neural network, through the characteristic line fitting and length extraction of the bottom edge line of steel structure, calculates the displacement and tension of steel structure, and analyzes the bridge deformation combined with arch displacement and shape variable. The research shows that using neural network to train the labeled data can effectively identify the characteristics of buildings and structures, and this technology can be applied to analyze local deformation of them.

Section extraction and deformation monitoring analysis of metro tunnel using TLS technology

PAN Dongfeng, YANG Chao, WU Yitong, TAN Tian, ZHANG Delin

2022, 0(4):  130-133.  doi:10.13474/j.cnki.11-2246.2022.0123

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In view of the shortcomings of traditional measurement methods, such as single results, complex process and low efficiency, in the extraction of metro tunnel cross-section and deformation monitoring, a surface fitting method based on the least square method is proposed for section extraction and deformation monitoring analysis using TLS technology in this paper. In this method,the continuous section of the tunnel is extracted based on the central axis of the tunnel, and the truncated section is fitted to a synthetic surface.The horizontal and vertical variation dimensions of the fitted surface are obtained through multiple surface comparisons, and then the deformation of the metro tunnel is calculated.Taking a tunnel in Xi'an metro as an example,compared with traditional monitoring methods,the proposed technique can quickly extract tunnel section and monitor deformation,effectively improving work efficiency.

Lane recognition of large radius circular curve based on vision

HUANG He, MENG Weiming

2022, 0(4):  134-137.  doi:10.13474/j.cnki.11-2246.2022.0124

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Lane line recognition is the key technology of lane keeping system in automatic driving. In order to improve the accuracy of lane line recognition of large radius circular curve, this algorithm divides the curved lanes on both sides into multiple regions, and uses straight line segment and Bezier curve to fit. Firstly, the image is preprocessed in the region of interest (ROI), and the turn is determined by the distribution of the feature pixels of the lane line according to the change law of the lane line. Then, the region of the left and right lane lines is divided according to different proportions and ways of the turn, and the line segments in the corresponding regions are identified by Hough transform, and the line segments less than the threshold are connected by lines. When the threshold value is higher than the set threshold value, the Bezier curve is used to connect and finally recognize the complete curved lane line. The experimental results show that the algorithm has good robustness to the recognition of large radius circular curve.

Vector rasterization method of national land use data in the third national land survey

ZHANG Dingxiang, WANG Xiulian, LIU Shunxi, ZHANG Jia, CHEN Qiang, LI Shijiang

2022, 0(4):  138-144.  doi:10.13474/j.cnki.11-2246.2022.0125

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The third national land survey county-level land use map layer contains multi-attribute information such as land use type, cultivated land type,slope grade,planting attribute,etc. It is difficult to integrate the county-level land use vector data to form a serials of national seamless multi-scale and multi- topic raster products. According to the application requirements of land use raster products in the third national land use survey,this paper discusses the technical methods of multi-attribute integrated coding,national basic geographic grid framework,raster product data model and rasterization,establishes the production flow of land use raster products in China,and conducts the production verification of multi-scale and multi-thematic land use raster products in China. The results show that the method can be used to rasterize the third national land use vector map to form national multi-scale and multi-topic land use raster products,which can provide support for the future land use raster products production and sharing application.

Research on construction of supervision information system for territorial spatial planning implementation involving provincial, prefectural and county levels:taking Guangdong province as an example

ZENG Yuanwu, SHI Jingwen, LUO Hongming, CHENG Yingxuan

2022, 0(4):  145-148.  doi:10.13474/j.cnki.11-2246.2022.0126

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Constructing the implementation of supervision information system and building "One Map", can provide information support for preparation, approval, implementation management, monitoring and warning, and shared services of territorial spatial planning. It's an important means to come true the "multiple planning integration", unify the spatial use regulation, and promote the modernization of the territorial spatial governance system and governance capabilities. In combination with the requirements of "digital government" construction, Guangdong province has constructed a supervision information system for implementation involving provincial, prefectural and county levels. Not only this system supports the digitalization of global territorial spatial, networking of spatial governance, intelligent planning and implementation of supervision, but also providing the suggestion for constructing the governance of territorial spatial planning data, a smart planning, implementation supervision system and the new model of "Internet + planning services".

Key technologies of building floor and house 3D modeling based on real estate registration data

XIONG Chengli, GONG Xuzheng, SHEN Zhengzhong, LONG Rong, WANG Shuo

2022, 0(4):  149-153.  doi:10.13474/j.cnki.11-2246.2022.0127

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With the continuous development of real 3D construction in China, city management is developing towards systematical, refined and digital. The floor and house 3D model of buildings can carry more detailed and accurate attribute information, and can render scene together with real three dimensional models, which can better serve the three dimensional management of city real estate and digital governance. Based on the background of "Xiaoshan district digital empowerment social governance" project construction, this paper discusses and realizes the key technology of building floor and house 3D modeling based on real estate registration data,forms technology in the manufacturing process which starts from the whole spatial multi-source heterogeneous data collection to floor&house 3D modeling of building all over the city,this technology can effectively provide technical support and data base for city real estate 3D management,digital enabling and social governance.

Application of data sharing mode based on blockchain technology:taking Beijing real estate registration as an example

PEI Lianlian, KONG Lingyan, REN Haiying, DONG Chengwei

2022, 0(4):  154-157.  doi:10.13474/j.cnki.11-2246.2022.0128

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In order to solve the problems of low usage rate and difficult application of data sharing among different departments, this paper proposes a new data sharing application model based on blockchain technology, taking real estate registration in Beijing as an example, this paper presents a practical solution for the secure and reliable use of the cross-departmental data sharing in real estate registration in Beijing by using the three ways of blockchain.

Volume calculation of glacier based on the theory of the SIA

ZENG Haixiao, LIU Wenwen

2022, 0(4):  158-161,166.  doi:10.13474/j.cnki.11-2246.2022.0129

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In this article, as examples of the Kangwure Glacier,the Gurenhekou Glacier,the Urumqi Glacier No.1 and the East Rongbuk Glacier,average thickness value of the every glacier mainstream line calculated by the theory of the SIA,DEM data and the glacier vector data,andevery ice volume is obtained by interpolation method.The results firstly show that the volume of the Kangwure Glacier,the Gurenhekou Glacier, the Urumqi Glacier No.1 and the East Rongbuk Glacier are about 0.022、0.026、0.024 and 1.450 km³.Furthermore, the ice volume based on the theory of the SIA are smaller which may relate to the precision of DEM data and sections division, compared with the ice volume based on the traditional empirical equations and GPR measured data.

Practical teaching instrument of LiDAR technology based on aviation simulation platform

XU Zhihua, LU Xingzheng, PENG Yuanhang, YANG Keming, WANG Yumin

2022, 0(4):  162-166.  doi:10.13474/j.cnki.11-2246.2022.0130

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In order to better understand the working principle of laser scanning technology and the whole process of 3D information acquisition, and to overcome the limitation of practical teaching in existing laser scanning course, especially airborne ones that is restricted by the practice sites, this paper introduces the self-developed laser scanning instrument for 3D data collection based on the aviation simulation platform (ASP) in the Shahe campus, China University of Mining and Technology-Beijing. The scanning instrument is developed by a single-pulse scanner and a rangefinder. First, this paper introduces the mathematical principle of the scanning instrument. Then, we design the method and scheme of 3D data acquisition in practical process with the developed scanning instrument. Finally, we conduct the experiments on 3D data acquisition and quality evaluation with the developed scanning instrument. The experimental results show that the accuracy of the scanning instrument for point clouds collection is better than 99%, which can provide effective practical support for practical experiments, innovation training and graduation project. Besides, the developed scanning instrument can be promoted to engineering applications such as storage square volume accounting.

Bridge deformation analysis based on point cloud slice extraction technique

WANG Bei, YE Xianfeng, WANG Junning

2022, 0(4):  167-171.  doi:10.13474/j.cnki.11-2246.2022.0131

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As a rapidly developing surveying and mapping tool in recent years, 3D laser scanning technology has become an important part of the monitoring technology in bridge health monitoring. In this paper, taking a cross-river bridge in Wuhan as an example, a Trimble SX10 3D laser scanner is used to scan the bridge for long-term monitoring, and the point clouds of the bridge steel structure and piers are sectioned. Then the scanned point clouds of each phase are processed with the help of Trimble Business Center and Trimble RealWorks software to extract the point coordinates of the bridge arch sections and perform the best vertical cylinder fitting of the bridge pier slicing point clouds. It obtains the coordinates of the fitted plane center points, compares and analyzes the deviations and 3D offsets of the plane coordinates of the feature points of each phase. The research results of this paper verify the feasibility of 3D laser scanner in bridge deformation monitoring, enrich the bridge monitoring data presentation, and can provide the basis and reference for related research.