2022 Vol. 47, No. 10
Display Method:
2022, 47(10): 1515-1522.
doi: 10.13203/j.whugis20220078
Abstract:
On September 16th, 2021, general secretary Xi Jinping pointed out in his congratulatory letter to the first international summit on BeiDou scale application: At present, the development of global digitalization is accelerating, and spatiotemporal information, location and navigation services have become an important new infrastructure. With the advent of the new infrastructure era, people engaged in surveying and mapping should think about what the country wants, be anxious about what the country is anxious about, and devote themselves to the wave of "the second 100 years" and "new infrastructure". Firstly, this paper expounds the definition of new infrastructure, and analyzes the difference between new infrastructure and traditional infrastructure. Secondly, it discusses the mission of geo-spatial information science in the three systems of new infrastructure, including information infrastructure, integration infrastructure and innovation infrastructure. The authors believed that we have walked through the so called traditional surveying and mapping which mainly serves topographic maps, and developed into the so called ubiquitous surveying and mapping which mainly focuses in the services of geo-spatial information. At present, we should seize the opportunity and expand the new mission of geo-spatial informatics science in the new infrastructure era, provide spatiotemporal data with good integrity, strong reality and high accuracy for the new infrastructure, and realize digital industrialization, industry digitization and intelligence.
On September 16th, 2021, general secretary Xi Jinping pointed out in his congratulatory letter to the first international summit on BeiDou scale application: At present, the development of global digitalization is accelerating, and spatiotemporal information, location and navigation services have become an important new infrastructure. With the advent of the new infrastructure era, people engaged in surveying and mapping should think about what the country wants, be anxious about what the country is anxious about, and devote themselves to the wave of "the second 100 years" and "new infrastructure". Firstly, this paper expounds the definition of new infrastructure, and analyzes the difference between new infrastructure and traditional infrastructure. Secondly, it discusses the mission of geo-spatial information science in the three systems of new infrastructure, including information infrastructure, integration infrastructure and innovation infrastructure. The authors believed that we have walked through the so called traditional surveying and mapping which mainly serves topographic maps, and developed into the so called ubiquitous surveying and mapping which mainly focuses in the services of geo-spatial information. At present, we should seize the opportunity and expand the new mission of geo-spatial informatics science in the new infrastructure era, provide spatiotemporal data with good integrity, strong reality and high accuracy for the new infrastructure, and realize digital industrialization, industry digitization and intelligence.
2022, 47(10): 1523-1534.
doi: 10.13203/j.whugis20220625
Abstract:
This paper introduces the current situation of constructing the seafloor geodetic network from design, layout, measurement, and data processing. Based on the requirements of national ocean strategy and the development of marine geodetic technology, the problems of the construction of seafloor geodetic networks at the present stage are analyzed. According to the results, it can be concluded the coverage of the current seafloor geodetic network is limited, and the information sharing is insufficient. In addition, the design and layout principles are not combined with the positioning precision of the network, which are mostly qualitative descriptions and lack operability. The accuracy and resolution of the sound velocity field are low and the measurement and data processing are difficult to meet the requirements of large-scale and high-precision underwater PNT (positioning, navigation and timing) network construction. To solve the mentioned problems, the concept of constructing the underwater PNT network with remote communication, information interconnection and telemetry is put forward. Several key technologies, including the design and layout of the underwater PNT network, the construction of the ocean sound velocity field with high precision and high resolution, the measurement strategy, data processing method and the thought of self-calibration and self-maintenance for underwater control points, the function of target and environment telemetry and sensing services, are discussed to provide support for the new generation of high-performance marine geodetic survey and the construction of underwater PNT network. It is believed that the proposed network system will lead to a revolution in underwater PNT construction when problems such as the optimal design of the large-scale network, enhancing positioning service, the accurate timing and time synchronization, remote communication and the extension of the application are broken through.
This paper introduces the current situation of constructing the seafloor geodetic network from design, layout, measurement, and data processing. Based on the requirements of national ocean strategy and the development of marine geodetic technology, the problems of the construction of seafloor geodetic networks at the present stage are analyzed. According to the results, it can be concluded the coverage of the current seafloor geodetic network is limited, and the information sharing is insufficient. In addition, the design and layout principles are not combined with the positioning precision of the network, which are mostly qualitative descriptions and lack operability. The accuracy and resolution of the sound velocity field are low and the measurement and data processing are difficult to meet the requirements of large-scale and high-precision underwater PNT (positioning, navigation and timing) network construction. To solve the mentioned problems, the concept of constructing the underwater PNT network with remote communication, information interconnection and telemetry is put forward. Several key technologies, including the design and layout of the underwater PNT network, the construction of the ocean sound velocity field with high precision and high resolution, the measurement strategy, data processing method and the thought of self-calibration and self-maintenance for underwater control points, the function of target and environment telemetry and sensing services, are discussed to provide support for the new generation of high-performance marine geodetic survey and the construction of underwater PNT network. It is believed that the proposed network system will lead to a revolution in underwater PNT construction when problems such as the optimal design of the large-scale network, enhancing positioning service, the accurate timing and time synchronization, remote communication and the extension of the application are broken through.
2022, 47(10): 1535-1545.
doi: 10.13203/j.whugis20210679
Abstract:
Geographic Information System has made great progress in theory and technology in recent 60 years. The application field of GIS has expanded to all aspects of society, and the social influence is increasable growing. The architecture, development mode and service mode of GIS have undergone profound changes. In order to promote the further development of GISystem, this paper focused on the following three issues based on summarizing the three meanings of "S" in "GIS", namely "System" "Science" and "Service", and the fruitful achievements of "GIS" in recent 60 years. The first issue is how to understand GISystem. This issue should be analyzed from two aspects, and one is to discuss the connotation of geographic information system through analyzing the three key words (namely system, information and geographic) of GIS. The other one is to analyze the relationship between GIS and map, computer mapping and map database. This paper holds the idea that GIS originates from and goes beyond map, computer mapping and map database. It should be considered that GIS has the characteristics of equipment. The second issue is how does GIS evolve. This issue focuses on the social demand background, technical background and discipline background of the development and evolution from "Geographic Information System" to "Geographic Information Service". It also focuses on the main manifestations of the development and evolution of GIS from the aspects of application field, expansion of data resources and functions, architecture, development mode and service mode. The third issue is where will the future development of GIS go. We discussed that the limit application domain expansion of GIS and point out that the future development of GIS must face the urgent needs of national economic construction and national defense construction. Based on the analysis and comparison of three existing GISystem service modes, we consider that the "hybrid" technology system of "grid integration" and "elastic cloud" is the best choice for GISystem service mode. Finally, this paper puts forward six key technical problems that must be solved in the implementation of "hybrid" spatiotemporal big data platform technology based on "grid integration" and "elastic cloud"and designs the application mode of "spatiotemporal big data platform".
Geographic Information System has made great progress in theory and technology in recent 60 years. The application field of GIS has expanded to all aspects of society, and the social influence is increasable growing. The architecture, development mode and service mode of GIS have undergone profound changes. In order to promote the further development of GISystem, this paper focused on the following three issues based on summarizing the three meanings of "S" in "GIS", namely "System" "Science" and "Service", and the fruitful achievements of "GIS" in recent 60 years. The first issue is how to understand GISystem. This issue should be analyzed from two aspects, and one is to discuss the connotation of geographic information system through analyzing the three key words (namely system, information and geographic) of GIS. The other one is to analyze the relationship between GIS and map, computer mapping and map database. This paper holds the idea that GIS originates from and goes beyond map, computer mapping and map database. It should be considered that GIS has the characteristics of equipment. The second issue is how does GIS evolve. This issue focuses on the social demand background, technical background and discipline background of the development and evolution from "Geographic Information System" to "Geographic Information Service". It also focuses on the main manifestations of the development and evolution of GIS from the aspects of application field, expansion of data resources and functions, architecture, development mode and service mode. The third issue is where will the future development of GIS go. We discussed that the limit application domain expansion of GIS and point out that the future development of GIS must face the urgent needs of national economic construction and national defense construction. Based on the analysis and comparison of three existing GISystem service modes, we consider that the "hybrid" technology system of "grid integration" and "elastic cloud" is the best choice for GISystem service mode. Finally, this paper puts forward six key technical problems that must be solved in the implementation of "hybrid" spatiotemporal big data platform technology based on "grid integration" and "elastic cloud"and designs the application mode of "spatiotemporal big data platform".
2022, 47(10): 1546-1554.
doi: 10.13203/j.whugis20220580
Abstract:
Objectives In recent years, the automatic ground object extraction from remote sensing images has been dramatically advanced by the fully convolutional networks (FCNs). It is an effective method to fuse high-resolution images and light detection and ranging (LiDAR) data in FCNs to improve the extraction accuracy and the robustness. However, the existing FCN-based fusion networks still face challenges in efficiency and accuracy. Methods We propose a knowledge-aware and multi-scale fusion network (KMFNet) for robust and accurate ground object extraction. The proposed network incorporates a knowledge-aware module in the network encoder for better exploiting remote sensing knowledge between pixels. A series-parallel hybrid convolution module is developed to enhance multi-scale representative features from ground objects. Moreover, the network decoder uses a gradual bilinear interpolation strategy to obtain fine-grained extraction results. Results We evaluate KMFNet in the LuoJiaNET with four current mainstream ground object extraction methods (GRRNet, V-FuseNet, DLR and Res-U-Net) on ISPRS 2D semantic segmentation dataset. The comparative evaluation results show that KMFNet can obtain the best overall accuracy. Compared with the other four methods, KMFNet achieves a better effect by improving the overall accuracy by 3.20% and 2.82% on average in ISPRS-Vaihingen dataset and ISPRS-Potsdam dataset, respectively. Conclusions KMFNet achieves the best extraction results by capturing the intrinsic pixel relationships and strengths the multi-scale representative and detailed features of ground objects. It shows great potential in high-precision remote sensing mapping applications.
2022, 47(10): 1555-1567.
doi: 10.13203/j.whugis20220412
Abstract:
The refined seafloor topography models play an important role in fields of submarine plate tectonic movement, underwater carrier navigation support and marine resource exploration and so on. This paper reviews the development of seafloor topography detection technology and model construction, and discusses the current research status and main challenges of the global refined seafloor topography modeling. Also, the developing trends of global seafloor topography modeling are summarized, considering that the technology of recovering seafloor topography from altimeter-derived marine gravity anomalies is still the main way to construct global seafloor topography models. New altimeter satellites such as dual satellite tandem altimeter and surface water ocean topography will provide data sources for further improving the accuracy of marine gravity field and seafloor topography models. Optimization of seafloor topographic inversion theory based on topographic complexity is expected to bring theoretical innovation. It is worth paying attention to explore the application of artificial intelligence technology in global seafloor topography modeling.
The refined seafloor topography models play an important role in fields of submarine plate tectonic movement, underwater carrier navigation support and marine resource exploration and so on. This paper reviews the development of seafloor topography detection technology and model construction, and discusses the current research status and main challenges of the global refined seafloor topography modeling. Also, the developing trends of global seafloor topography modeling are summarized, considering that the technology of recovering seafloor topography from altimeter-derived marine gravity anomalies is still the main way to construct global seafloor topography models. New altimeter satellites such as dual satellite tandem altimeter and surface water ocean topography will provide data sources for further improving the accuracy of marine gravity field and seafloor topography models. Optimization of seafloor topographic inversion theory based on topographic complexity is expected to bring theoretical innovation. It is worth paying attention to explore the application of artificial intelligence technology in global seafloor topography modeling.
2022, 47(10): 1568-1575.
doi: 10.13203/j.whugis20220576
Abstract:
Digital development has been vigorously promoted in China to drive a comprehensive and in-depth change in production, life and governance through the construction of digital economy, digital society and digital government. It has put forward new and higher requirements for basic surveying and mapping products and services. Recently, the Ministry of Natural Resources of the People's Republic of China issued a notice to promote the construction of 3D realistic geospatial scene of China, aiming to develop new 3D geo-spatial information products which can describe and represent the real 3D spaces of industrial production, living environment and ecological development. The construction of such 3D realistic geospatial scene of China will lead to a 3D digital space which can be well connected with the real geo-spatial space through real-time inter-connection, and will provide a new generation of spatiotemporal information framework for the development of digital China. It is not only a major task for national and local basic surveying and mapping agencies in the next few decades, but also a challenging scientific and technological initiative where several complex factors and technical problems remain to be solved. This paper analyzes the background and problems, discusses the development directions and general technical logic, and conductes the major technological path.
Digital development has been vigorously promoted in China to drive a comprehensive and in-depth change in production, life and governance through the construction of digital economy, digital society and digital government. It has put forward new and higher requirements for basic surveying and mapping products and services. Recently, the Ministry of Natural Resources of the People's Republic of China issued a notice to promote the construction of 3D realistic geospatial scene of China, aiming to develop new 3D geo-spatial information products which can describe and represent the real 3D spaces of industrial production, living environment and ecological development. The construction of such 3D realistic geospatial scene of China will lead to a 3D digital space which can be well connected with the real geo-spatial space through real-time inter-connection, and will provide a new generation of spatiotemporal information framework for the development of digital China. It is not only a major task for national and local basic surveying and mapping agencies in the next few decades, but also a challenging scientific and technological initiative where several complex factors and technical problems remain to be solved. This paper analyzes the background and problems, discusses the development directions and general technical logic, and conductes the major technological path.
2022, 47(10): 1576-1586.
doi: 10.13203/j.whugis20220234
Abstract:
Establishing a unified global height datum is one of the core objectives of the international geodetic scientific community, and also a necessary infrastructure for geoscience research on a global scale and cross-border engineering applications. The international geodesy association (IAG) released the definition of international height reference system (IHRS) in 2015 and then in 2019 set out the goal of establishing the international height reference frame (IHRF). In this paper, the theory, methods and practical problems related to the IHRS and IHRF are reviewed and studied on the basis of the theoretical foundation and definition of the global height reference system. The main research contents include the determination of gravity potentialW 0
Establishing a unified global height datum is one of the core objectives of the international geodetic scientific community, and also a necessary infrastructure for geoscience research on a global scale and cross-border engineering applications. The international geodesy association (IAG) released the definition of international height reference system (IHRS) in 2015 and then in 2019 set out the goal of establishing the international height reference frame (IHRF). In this paper, the theory, methods and practical problems related to the IHRS and IHRF are reviewed and studied on the basis of the theoretical foundation and definition of the global height reference system. The main research contents include the determination of gravity potential
2022, 47(10): 1587-1597.
doi: 10.13203/j.whugis20220079
Abstract:
Objectives To satisfy the widely demand of 3D real scene reconstruction, a novel unmanned aerial vehicle (UAV) photogrammetric technique approach, named optimized views photogrammetry, is presented. Methods In terms of the 3D rough model of the scene which obtained in various ways, optimized views photogrammetry generates initial views via stereoscopic observation sampling and selects optimal views under the constraint of observability measure, and then forms the aerial photogrammetry planning path for quadcopters. For the contradiction between large-scale application and limited endurance of UAV system, optimized views photogrammetry provides a multi-UAV collaborative survey solution with its specific path division function in the planning end. A practical application verification was performed in urban central district of Qingdao, to assess the performance of multi-UAV cooperative optimized views photogrammetry in relatively large range complicated urban scene. Results The output results of real 3D reconstruction postprocessing and the detailed comparison with the model generated from oblique photogrammetry verify that, on the premise of high-quality real scene 3D output, the technical approach realizes the real scene 3D acquisition in a large range of complex space with light and small aerial photography equipment, as meanwhile and improves the efficiency through collaborative operation. Conclusions With the key support of optimized views photogrammetry, it could also make an extension to the new technology application mode of ubiquitous real 3D data acquisition for multiple technical directions and application fields.
2022, 47(10): 1598-1614.
doi: 10.13203/j.whugis20220603
Abstract:
The optimal allocation of land-use is an important technical means to solve the contradiction between supply and demand of land resources and to coordinate social and economic development with ecolog?ical protection, and it is also one of the key issues that need to be solved for the sustainable use of land resources. With the development of spatial simulation and intelligent optimization technology, the theoretical basis and methodological system of land-use optimization are constantly updated. Based on bibliometrics analysis, this paper systematically summarized the driving theories and methodology of land-use optimal allocation at home and abroad, focused on the application of spatial simulation models and intelligent optimization models in land-use optimization problems, discussed and prospected the challenges and the future development of optimal land-use allocation, and put forward that: The coupling drive of natural and human processes, spatial collaboration of multiple models, embedding big data knowledge mining methods, and the support of digital twin technology, should be the research direction of the next stage in the field of optimal land-use allocation.
The optimal allocation of land-use is an important technical means to solve the contradiction between supply and demand of land resources and to coordinate social and economic development with ecolog?ical protection, and it is also one of the key issues that need to be solved for the sustainable use of land resources. With the development of spatial simulation and intelligent optimization technology, the theoretical basis and methodological system of land-use optimization are constantly updated. Based on bibliometrics analysis, this paper systematically summarized the driving theories and methodology of land-use optimal allocation at home and abroad, focused on the application of spatial simulation models and intelligent optimization models in land-use optimization problems, discussed and prospected the challenges and the future development of optimal land-use allocation, and put forward that: The coupling drive of natural and human processes, spatial collaboration of multiple models, embedding big data knowledge mining methods, and the support of digital twin technology, should be the research direction of the next stage in the field of optimal land-use allocation.
2022, 47(10): 1615-1624.
doi: 10.13203/j.whugis20220021
Abstract:
Objectives The stochastic model of observation information describes the accuracy of observation information and its correlation, and also plays an important role in parameter estimation, quality control and accuracy evaluation. In the process of global navigation satellite system (GNSS) precision positioning, an accurate stochastic model is essential for improving the accuracy of float solution, enhancing the success rate of ambiguity resolution, increasing the accuracy of gross error detection, and obtaining the accurate and reliable positioning results. Methods An optimization method for stochastic model of BeiDou navigation satellite system (BDS) is proposed by handling the properties of four classic elevation-dependent stochastic models based on the relationship between BDS satellite observation information and elevation. Firstly, the accuracy of BDS four-frequency observation information is evaluated by the simplified Helmert variance estimation method. Then, the model parameters could be fitted based on the estimated precision of observation information. Finally, the statistical characteristics of four stochastic models, including piecewise function, sine function, cosine function and exponential function, are tested by the overall test and ω-test methods. Results The results show that the accuracy of pseudorange and carrier phase for BDS-3 satellite are related to elevation, and the correlation degree is different by GNSS observation types. The stochastic model of exponential function shows the best performance in the fitting error, the overall test and the ω-test. The maximum fitting errors of pseudorange and carrier phase are 0.029 m and 5.484 mm, respectively. The false alarm rates of the overall test for the float solution and the fixed solution are 5.1 % and 4.9 %, respectively. In addition, the maximum false alarm rates of the ω-test are 5.8 % for the pseudorange and 6.8 % for the carrier phase. Conclusions The stochastic model of exponential function can get the shortest convergence time and the highest positioning accuracy for BDS-3 quad-frequency precise point positioning. It can also accurately describe the accuracy of BDS observation information and improve the accuracy and reliability of BDS precise positioning results.
2022, 47(10): 1625-1634.
doi: 10.13203/j.whugis20220589
Abstract:
Deformation monitoring is an important guarantee for the safe operation of water conservancy projects. With the advantages of high precision, all-day and all-climate observation, global satellite navigation system (GNSS) provides new means for deformation monitoring in hydraulic engineering. At present, the deformation monitoring technologies represented by satellite positioning is approaching intelligent development in all processes, all aspects, and all autonomous.Firstly, we focus on the demand of deformation monitoring of water conservancy projects, and review the development of deformation monitoring technology. Then, the application of GNSS deformation monitoring in hydraulic engineering is introduced. Besides, the difficulties and limitations of GNSS deformation monitoring application are discussed. Finally, the development direction of intelligent GNSS deformation monitoring in hydraulic engineering in the future is prospected.
Deformation monitoring is an important guarantee for the safe operation of water conservancy projects. With the advantages of high precision, all-day and all-climate observation, global satellite navigation system (GNSS) provides new means for deformation monitoring in hydraulic engineering. At present, the deformation monitoring technologies represented by satellite positioning is approaching intelligent development in all processes, all aspects, and all autonomous.Firstly, we focus on the demand of deformation monitoring of water conservancy projects, and review the development of deformation monitoring technology. Then, the application of GNSS deformation monitoring in hydraulic engineering is introduced. Besides, the difficulties and limitations of GNSS deformation monitoring application are discussed. Finally, the development direction of intelligent GNSS deformation monitoring in hydraulic engineering in the future is prospected.
2022, 47(10): 1635-1650.
doi: 10.13203/j.whugis20210561
Abstract:
Marine and airborne gravimetry is principal to obtain marine gravity field information. To meet the practical requirements of building and expanding of civil military integration system of marine and airborne gravity surveying technology, we have been devoted to the research on theory and method of marine and airborne gravimetry and its application. A detail analysis and review is made based on the research results with theoretical significances and practical values. The study of marine and airborne gravimetry and its application, which are achieved by our research team, mainly covers demand demonstration and top-level design, observation data reduction and accuracy evaluation, observation error analysis processing and separation compensation, upward continuation of observation gravity on the Earth's surface, downward continuation of airborne gravity, construction of gravity data model at sea, approximation of the Earth's external gravity field and geoid refinement, etc. The research background, idea and breakthrough point of each topic, and the applicable prospect of research results are mainly analyzed and summarized. We pay our attention to the design of technical framework, the building of variation character models of marine gravity field and the surveying line layout for marine gravity survey, the design of key technical targets for marine and airborne gravimetry, the rising mechanism and compensation of marine and airborne gravity surveying errors, the integrated application of marine and airborne gravity measurement data, and so on. This paper can provide a reference for the future development of marine and airborne gravimetry.
Marine and airborne gravimetry is principal to obtain marine gravity field information. To meet the practical requirements of building and expanding of civil military integration system of marine and airborne gravity surveying technology, we have been devoted to the research on theory and method of marine and airborne gravimetry and its application. A detail analysis and review is made based on the research results with theoretical significances and practical values. The study of marine and airborne gravimetry and its application, which are achieved by our research team, mainly covers demand demonstration and top-level design, observation data reduction and accuracy evaluation, observation error analysis processing and separation compensation, upward continuation of observation gravity on the Earth's surface, downward continuation of airborne gravity, construction of gravity data model at sea, approximation of the Earth's external gravity field and geoid refinement, etc. The research background, idea and breakthrough point of each topic, and the applicable prospect of research results are mainly analyzed and summarized. We pay our attention to the design of technical framework, the building of variation character models of marine gravity field and the surveying line layout for marine gravity survey, the design of key technical targets for marine and airborne gravimetry, the rising mechanism and compensation of marine and airborne gravity surveying errors, the integrated application of marine and airborne gravity measurement data, and so on. This paper can provide a reference for the future development of marine and airborne gravimetry.
2022, 47(10): 1651-1661.
doi: 10.13203/j.whugis20220184
Abstract:
Underground coal fire is widely distributed and repeatedly treated, causing waste of resources and ecological damage. China is the country with the most serious coal spontaneous combustion disaster in the world, 80% of coal seams have the tendency to spontaneous combustion. Rapid, comprehensive, timely and accurate detection of hidden fire sources in coalfields is the basis and prerequisite for fire prevention, extinguishing and ecological management. Multi-source remote sensing has a great potential for the applications, but it needs to penetrate the surface and go deep underground, and there are many bottlenecks to be solved. Firstly, the problem of multi-source remote sensing detection of hidden fires in coalfields is abstracted into the key nodes of same source (same underground spontaneous combustion source), multi-phenomenon (various abnormal phenomena formed on the surface), multi-image (photographed by multi-source remote sensing, including a variety of surface image of abnormal information). Meanwhile, the research chain of multiple phenomena is analyzed, which includes the same source, the phenomenon to image mapping, the transmission from source to phenomenon, and the multiple image recognition source. On these basis, the technical bottleneck of multi-source remote sensing detection of concealed fire sources in coalfields is discussed. Secondly, based on the research examples of concealed fire detection in coal fire areas of Fukang, Miquan and Bao'an in the Xinjiang Uygur Autonomous Regions, China, we give the research progress and effects of polarized time-series interferometric synthetic aperture radar (InSAR) fire area deformation detection, spatio-temporal temperature threshold method fire area delineation, multi-source satellite remote sensing fire area identification, and unmanned aerial vehicle fire area monitoring experiment. Finally, the development direction of integrating multi-source satellite remote sensing images and space-sky-ground-mine cooperative perception cognitions is prospected.
Underground coal fire is widely distributed and repeatedly treated, causing waste of resources and ecological damage. China is the country with the most serious coal spontaneous combustion disaster in the world, 80% of coal seams have the tendency to spontaneous combustion. Rapid, comprehensive, timely and accurate detection of hidden fire sources in coalfields is the basis and prerequisite for fire prevention, extinguishing and ecological management. Multi-source remote sensing has a great potential for the applications, but it needs to penetrate the surface and go deep underground, and there are many bottlenecks to be solved. Firstly, the problem of multi-source remote sensing detection of hidden fires in coalfields is abstracted into the key nodes of same source (same underground spontaneous combustion source), multi-phenomenon (various abnormal phenomena formed on the surface), multi-image (photographed by multi-source remote sensing, including a variety of surface image of abnormal information). Meanwhile, the research chain of multiple phenomena is analyzed, which includes the same source, the phenomenon to image mapping, the transmission from source to phenomenon, and the multiple image recognition source. On these basis, the technical bottleneck of multi-source remote sensing detection of concealed fire sources in coalfields is discussed. Secondly, based on the research examples of concealed fire detection in coal fire areas of Fukang, Miquan and Bao'an in the Xinjiang Uygur Autonomous Regions, China, we give the research progress and effects of polarized time-series interferometric synthetic aperture radar (InSAR) fire area deformation detection, spatio-temporal temperature threshold method fire area delineation, multi-source satellite remote sensing fire area identification, and unmanned aerial vehicle fire area monitoring experiment. Finally, the development direction of integrating multi-source satellite remote sensing images and space-sky-ground-mine cooperative perception cognitions is prospected.
2022, 47(10): 1662-1674.
doi: 10.13203/j.whugis20220130
Abstract:
Objectives Incremental structure from motion (SfM) has become the widely used workflow for aerial triangulation (AT) of unmanned aerial vehicle (UAV) images. Recently, extensive research has been conducted to improve the efficiency, precision and scalability of SfM-based AT for UAV images. Meanwhile, deep learning-based methods have also been exploited for the geometry processing in the fields of photogrammetry and computer vision, which have been verified with large potential in the AT of UAV images. This paper aims to give a review of recent work in the SfM-based AT for UAV images. Methods Firstly, the workflow of SfM-based AT is briefly presented in terms of feature matching and geometry solving, in which the former aims to obtain enough and accurate correspondences, and the latter attempts to solve unknown parameters. Secondly, literature review is given for feature matching and geometry solving. For feature matching, classical hand-crafted and recent learning-based methods are presented from the aspects of feature extraction, feature matching and outlier removal. For geometry solving, the principle of SfM-based AT is firstly given with some well-known and widely-used open-source SfM software. Efficiency improvement and large-scale processing are then summarized, which focus on improving the capability of SfM to process large-scale UAV images. Finally, further search is concluded from four aspects, including the change of data acquisition modes, the scalability for large-scale scenes, the development of communication and hardware, and the fusion of deep learning-based methods. Results The review demonstrates that the existing research promotes the development of SfM-based AT towards the direction of high efficiency, high precision and high robustness, and also promotes the development of both commercial and open-source software packages. Conclusions Considering the characteristics of UAV images, the efficiency, precision and robustness of SfM-based AT and its application need further improvement and exploitation. This paper could give an extensive conclusion and be a useful reference to the related researchers.
2022, 47(10): 1675-1687.
doi: 10.13203/j.whugis20210687
Abstract:
Map generalization is one of the core technologies of cartography and multi-scale spatial data transformation. Since the 1960s, the research on the automated generalization of map data has gradually developed and made great progress. Furthermore, there are many intelligent solutions on map generalization. However, due to the limitation of the artificial intelligence technology, these intelligent solutions on map generalization are not really intelligent and practical. In the past 10 years, deep learning, as a presentative artificial intelligence technology, was applied in many fields, and the deep-learning-based researches achieved remarkable results. And thus, many new attempts have been made in the intelligent research of map generalization. Firstly, based on analyzing and abstracting models of the automated map generalization, the necessity of the intelligent research on map generalization is pointed out. Secondly, combining with the development of artificial intelligence, the intelligent map generalization is overviewed. Researches of intelligent map generalization based on traditional machine learning and deep learning are sorted and analyzed, and two common strategies of intelligent map generalization are summarized. Finally, focusing on some hot issues of intelligent map generalization, the development tendency of intelligent map generalization is discussed.
Map generalization is one of the core technologies of cartography and multi-scale spatial data transformation. Since the 1960s, the research on the automated generalization of map data has gradually developed and made great progress. Furthermore, there are many intelligent solutions on map generalization. However, due to the limitation of the artificial intelligence technology, these intelligent solutions on map generalization are not really intelligent and practical. In the past 10 years, deep learning, as a presentative artificial intelligence technology, was applied in many fields, and the deep-learning-based researches achieved remarkable results. And thus, many new attempts have been made in the intelligent research of map generalization. Firstly, based on analyzing and abstracting models of the automated map generalization, the necessity of the intelligent research on map generalization is pointed out. Secondly, combining with the development of artificial intelligence, the intelligent map generalization is overviewed. Researches of intelligent map generalization based on traditional machine learning and deep learning are sorted and analyzed, and two common strategies of intelligent map generalization are summarized. Finally, focusing on some hot issues of intelligent map generalization, the development tendency of intelligent map generalization is discussed.
2022, 47(10): 1688-1700.
doi: 10.13203/j.whugis20220126
Abstract:
The mm-level dynamic maintenance technology is essential to the realization of mm-level terrestrial reference frames. The current dynamic maintenance technology mainly includes the linear maintenance based on linear velocity, the nonlinear maintenance technology that comprehensively considers the nonlinear motion of stations and geocentric motion, and the epoch reference frame. Firstly, the development status of the linear maintenance technology is summarized. The nonlinear maintenance technology and its research progress are discussed by reviewing the modelling method of coordinate nonlinear variation from the influence mechanism and data. Then, the realization process of the epoch reference frame and its application in the maintenance of the reference frames are introduced. Finally, based on the analysis of status quo, several key issues that need to be solved are proposed to achieve the dynamic maintenance of the mm-level terrestrial reference frame.
The mm-level dynamic maintenance technology is essential to the realization of mm-level terrestrial reference frames. The current dynamic maintenance technology mainly includes the linear maintenance based on linear velocity, the nonlinear maintenance technology that comprehensively considers the nonlinear motion of stations and geocentric motion, and the epoch reference frame. Firstly, the development status of the linear maintenance technology is summarized. The nonlinear maintenance technology and its research progress are discussed by reviewing the modelling method of coordinate nonlinear variation from the influence mechanism and data. Then, the realization process of the epoch reference frame and its application in the maintenance of the reference frames are introduced. Finally, based on the analysis of status quo, several key issues that need to be solved are proposed to achieve the dynamic maintenance of the mm-level terrestrial reference frame.
2022, 47(10): 1701-1712.
doi: 10.13203/j.whugis20220446
Abstract:
The study of asperities is of great importance for seismic hazard analysis. This paper introduces the concepts of asperities, barriers and their source models, and reviews the progress of research on the determination of asperities by seismic geodesy, mainly discusses the technique and method for determining asperities from the aspects of medium structure analysis (high-intensity anomalies), seismic activity analysis, the fault slip pattern, and the problems are analyzed. This paper also prospects the determination of the distribution of asperities on active faults, future researches will focus on joint inversion of geodetic data, joint geodetic and seismic geophysical data, and machine learning based methods to determinate the distribution of asperities. The study provides a strong theoretical basis for seismic safety evaluation.
The study of asperities is of great importance for seismic hazard analysis. This paper introduces the concepts of asperities, barriers and their source models, and reviews the progress of research on the determination of asperities by seismic geodesy, mainly discusses the technique and method for determining asperities from the aspects of medium structure analysis (high-intensity anomalies), seismic activity analysis, the fault slip pattern, and the problems are analyzed. This paper also prospects the determination of the distribution of asperities on active faults, future researches will focus on joint inversion of geodetic data, joint geodetic and seismic geophysical data, and machine learning based methods to determinate the distribution of asperities. The study provides a strong theoretical basis for seismic safety evaluation.
2022, 47(10): 1713-1727.
doi: 10.13203/j.whugis20220537
Abstract:
Satellite gravimetry is an efficient technical means to detect the global consistent, high-precision and high-resolution Earth's gravity field, mainly including high-low satellite-to-satellite tracking (SST-hl), low-low satellite-to-satellite tracking (SST-ll) and satellite gravity gradiometry (SGG). We summarize the main methods to recover the earth's gravity field from satellite gravimetry technologies (including SST-hl, SST-ll, SGG and multi-mode combination), and review the latest progress in constructing the static and time-variable gravity field models using challenging mini-satellite payload(CHAMP), gravity recovery and climate experiment(GRACE)/GRACE follow-on(GRACE-FO) and gravity field and steady-state ocean circulation explorer(GOCE) satellite gravity measurements. And the accuracies of the current representative static and time-variable gravity field models are analyzed and evaluated. It is expected to provide reference for the study of the Earth's gravity field and its geoscience application in the future.
Satellite gravimetry is an efficient technical means to detect the global consistent, high-precision and high-resolution Earth's gravity field, mainly including high-low satellite-to-satellite tracking (SST-hl), low-low satellite-to-satellite tracking (SST-ll) and satellite gravity gradiometry (SGG). We summarize the main methods to recover the earth's gravity field from satellite gravimetry technologies (including SST-hl, SST-ll, SGG and multi-mode combination), and review the latest progress in constructing the static and time-variable gravity field models using challenging mini-satellite payload(CHAMP), gravity recovery and climate experiment(GRACE)/GRACE follow-on(GRACE-FO) and gravity field and steady-state ocean circulation explorer(GOCE) satellite gravity measurements. And the accuracies of the current representative static and time-variable gravity field models are analyzed and evaluated. It is expected to provide reference for the study of the Earth's gravity field and its geoscience application in the future.
2022, 47(10): 1728-1739.
doi: 10.13203/j.whugis20220364
Abstract:
Ionosphere is an important part of the near-earth space environment, and it has an important impact on radio communication, satellite navigation and positioning. Therefore, monitoring the ionospheric morphology is helpful to understand the spatiotemporal changes of the ionosphere and predict the ionospheric morphological characteristics. With the development of global navigation satellite system(GNSS), ionospheric monitoring has become an important research and application direction. This paper systematically introduces the research progress of multidimensional GNSS ionospheric monitoring and its application in related aspects. It mainly includes space-based/ground-based GNSS joint inversion of ionospheric characteristic parameters, tomography inversion of ionospheric three-dimensional structure, ionospheric delay modeling, ionospheric abnormal disturbance monitoring and mechanism cognition.
Ionosphere is an important part of the near-earth space environment, and it has an important impact on radio communication, satellite navigation and positioning. Therefore, monitoring the ionospheric morphology is helpful to understand the spatiotemporal changes of the ionosphere and predict the ionospheric morphological characteristics. With the development of global navigation satellite system(GNSS), ionospheric monitoring has become an important research and application direction. This paper systematically introduces the research progress of multidimensional GNSS ionospheric monitoring and its application in related aspects. It mainly includes space-based/ground-based GNSS joint inversion of ionospheric characteristic parameters, tomography inversion of ionospheric three-dimensional structure, ionospheric delay modeling, ionospheric abnormal disturbance monitoring and mechanism cognition.
2022, 47(10): 1740-1749.
doi: 10.13203/j.whugis20220611
Abstract:
Objectives Smartphones have become the mainstream terminal carrier of navigation and location services for mass users by virtue of their ubiquity, portability, and low cost. With the opening of their multi-frequency and multi-constellation global navigation satellite system (GNSS) observations, the research on high-precision positioning of smartphones has been further stimulated. However, limited by the performance of consumer-grade GNSS devices, the satellite observations of smartphones present problems such as serious signal attenuation, large pseudorange noise, and many cycle slips; and also affected by the complex urban environment, the continuity and reliability of smartphone GNSS positioning is also difficult to guarantee. Methods A smartphone GNSS/MEMS (micro-electro mechanical system) integrated high-precision positioning scheme for vehicular navigation in urban conditions is proposed. Firstly, a velocity-constrained GNSS differential filtering positioning model is constructed to realize precise positioning in a general observation environment; then, through the built-in MEMS of smartphone and virtual constraints of vehicle motion, GNSS precise positioning is enhanced in challenging environments. Results The experiment results show that, in open sky and tree occlusion conditions, the improved method can achieve decimeter-to-meter positioning accuracy, which is 35.2% and 78.9% higher than conventional method, respectively; in viaduct occlusion conditions, the accuracy and continuity of GNSS/MEMS fusion positioning are the best; in tunnel conditions, the cumulative position error of the MEMS mechanization is about 2.5%. Conclusions The results preliminarily show that smartphone GNSS has lane-level positioning capabilities in open-sky environments, and GNSS/MEMS fusion can improve the accuracy and continuity of smartphone positioning in urban challenging environments.
2022, 47(10): 1750-1757.
doi: 10.13203/j.whugis20210643
Abstract:
Objectives Coastal sea level rise poses direct threats to human livelihood. It is of scientific importance to understand the causes and provide useful strategies for adapting sea level rise. This paper aims to investigate the causes of coastal sea level change using satellite altimetry, satellite time-variable gravity, and Argo floats. Methods Given that time-variable gravity suffers from serious leakage issue over coastal area, we use land mass variations from a mascon solution to simulate the leakage from land into oceans, which is estimated to be 0.68 mm/a. Results On seasonal and non-seasonal scales, satellite altimetry measurements are well explained by the summation of time-variable gravity and Argo floats, demonstrating the closure of coastal sea level change.Satellite altimetry suggests a rate of 3.32±0.45 mm/a for coastal sea level rise, but the summation of time-variable gravity and Argo floats yields a rate of 2.25±0.51 mm/a. Conclusions The rate discrepancy is about 1 mm/a in coastal sea level budget, which suggestes that closing the sea level budget for coastal zone is challenged by uncertainties. The in situ measurements are sparse for Argo over coastal zone, which may underestimate the steric trend. Furthermore, leakage correction and vertical land motion may also cause uncertainties.
2022, 47(10): 1758-1765.
doi: 10.13203/j.whugis20220456
Abstract:
Objectives The measuring accuracy of the multilateral method is affected by the station layout and the calibration errors of system parameters. The optimal station layout and new system parameters calibration method are investigated for optimizing the multilateral method. Methods A spherical center fitting method is introduced to calibrate station coordinates without enhanced reference points. Besides, according to the model error of the multilateral method, the optimal station layout is an equilateral rectangular triangular pyramid. Results In the range of 5 m, the root mean square error (RMSE) of system parameters calibration based on spherical center fitting method is less than 0.006 4 mm, and the RMSE of coordinate measurement of point inside the optimal station layout is less than 0.005 mm. Within the survey region of 5 m, the RMSE of length measurement is less than 0.003 6 mm using optimized multilateral method, and the RMSE of coordinate measurement of optimized multilateral method is less than 0.005 3 mm. Conclusions The optimized multilateral method can achieve high-precision coordinate measurement in a small region. The large-scale 3D coordinate measurement will be studied later using multilateral method.
2022, 47(10): 1766-1774.
doi: 10.13203/j.whugis20220616
Abstract:
Objectives Classical physics geodetic mainly focuses on the solution of the geodetic boundary value problem, which is usually given by the theorems of Stokes and Molodensky. Solving the internal gravity field of the ocean is a problem of solving the internal potential of the earth, to which classical theoretical method cannot be applied. In order to solve this limitation, the concept of shallow seawater is introduced based on the surface shallow method to calculate the internal ocean gravity at different depths. Methods Using high-resolution data of DTU21 mean sea surface and EGM2008, combined with Newton's integration, spherical harmonic analysis, and spherical harmonic comprehensive theoretical methods, the internal ocean gravity field in the western Pacific region ((131.5°±0.25°) E, (19.5°±0.25°) N) was determined. The number of iterations of spherical harmonic analysis was determined, and the relationship between the depth of shallow seawater and the integral area radius was analyzed. Results and Conclusions An optimal integral area radius of 1° was determined for 100 m, 500 m and 1 000 m and the depth of 1.5° for 4 000 m. The accuracy of the shallow seawater method to remove-restore the ocean surface gravity is evaluated and the root mean square error is 0.13 mGal at a depth of 100 m, 0.61 mGal at a depth of 500 m, 1.21 mGal at a depth of 1 000 m, and 3.93 mGal at a depth of 4 000 m. Compared to surface gravity, gravity of the inner layer of the ocean increases by 22.11 mGal at 100 m depth, 110.50 mGal at 500 m depth, 220.87 mGal at 1 000 m depth, and 877.31 mGal at 4 000 m depth.
2022, 47(10): 1775-1784.
doi: 10.13203/j.whugis20220486
Abstract:
Objectives Sporadic E (Es) layers, the thin layers with enhanced electron density sporadically appearing at the altitude range of 90 to 120 km, can cause strong fluctuations in the amplitudes measurements of global navigation satellite system (GNSS) radio occultation (RO). Methods We use the 50 Hz signal-to-noise ratio (SNR) data of global positioning system (GPS) RO observations from the Fengyun-3C (FY3C) and Fengyun-3D (FY3D) satellites to detect the existences of Es layers, based on which the spatiotemporal distributions and seasonal variations of Es occurrences at the latitudes of 60°S-60°N during 2019-01 to 2021-12 are derived and compared. Results It is found that the Es morphologies derived using the RO data from the two satellites independently are basically in accordance with each other, which both reflect the close relationships of the Es occurrences with the geomagnetic field and the neutral wind field. While the Es occurrences derived from FY3C are generally higher than those derived from FY3D in most seasons and over different regions, which is especially distinct in the summer season of the middle latitudes over the northern hemisphere, and the FY3C-derived Es morphology is more consistent with previous studies based on COSMIC (the constellation observing system for meteorology, lonosphere, and climate) RO data. Conclusions Several factors should contribute to the differences between the Es morphologies derived from the RO observations of the two satellites, including the differences in the top heights of the SNR profiles, the differences in the local time coverages of the RO observations from the two satellites, and the different noise levels of the global navigation occultation sounders (GNOSs) on the two satellites. Our results indicate that the Es detection strategy might need to be adjusted according to the noise level of the GNOSs when combining the RO data from two satellites.
2022, 47(10): 1785-1795.
doi: 10.13203/j.whugis20210658
Abstract:
Objectives Due to the joint constraints of boundary conditions, including seabed topography, driven water level at open boundary (DWLOB) and bottom friction coefficient (BFC), the accuracy of the tidal numerical modeling in coastal and offshore waters is relatively low. Methods This paper intends to synchronously optimize the multiple boundary conditions, including seabed topography, DWLOB, and BFC, to improve the accuracy of the tidal numerical modeling in China's coastal and offshore waters for the hydrographic surveying and mapping. This paper simulates the tidal model of Haizhou Bay of the Yellow Sea in China, using a two-dimensional tide numerical model (2D-MIKE21) and based on the synchronously optimized boundary conditions. The water depth with higher resolution and accuracy than the charted depth is used as the seabed topography. The DWLOB is calculated from 12 tidal constituents of the regional tidal model of China seas(CST1). The calculation of the BFC takes into account the spatial variation of water depth. Results For validation, we compare the simulated model with the 1-year tide tables from 6 tide gauges in Haizhou Bay and the CST1 model at 24 randomly selected points, and get the total root sum squares of the 12 tidal constituents of 5.52 cm and 7.10 cm, respectively. The simulated tide model and CST1 are also compared with the 1-month observations at two tide gauges in Haizhou Bay, and the former has a smaller mean square error than the latter. Conclusions The proposed strategy provides a new method for tidal numerical modeling in coastal and offshore waters. This study also shows that it is feasible to obtain the astro-meteorological constituent Sa by tidal numerical modeling. It should be noted that, the wind effect is also not considered in this study due to its strong randomness and the difficulty in obtaining data for one year. We can use the simulated water level heights and the short-term wind velocity and direction as the better open boundary and initial conditions to carry out the short-term tidal modeling in coastal and offshore waters, which can generate the residual water level or storm surge.
2022, 47(10): 1796-1804.
doi: 10.13203/j.whugis20210584
Abstract:
Objectives Accurate and reliable prediction of watershed groundwater storage can help ensure the sustainable use of a watershed's aquifers for urban and rural water supply. Methods On the basis of precipitation information, gravity recovery and climate experiment (GRACE) and global land data assimilation system (GLDAS), the prediction of groundwater storage is performed by using the seasonal adjustment and non-linear autoregressive(NAR) neural network. The NAR model without the seasonal adjustment, the autoregressive (AR) model, and the seasonal autoregressive integrated moving average (SARIMA) model are compared. Results Taking the Changjiang Basin, the Lena Basin, the Ob Basin and the Yenisey Basin as case studies, the results indicate that the deseasonalized precipitation is independent and the groundwater is good fit to AR(1), which lay the foundations of deciding the number of a time delay of the NAR neural network. The performance of the NAR neural network using the seasonal adjustment falls into the excellent category for each basin and shows superiority over AR model and SARIMA model, with root mean square error less than 1 cm and correlation coefficient more than 0.96. Conclusions The integration of seasonal adjustment technique and NAR neural network can not only improve the prediction accuracy of groundwater storage, but also reduce the convergence time. The proposed method can effectively forecast the groundwater storage with improved performance due to the seasonal adjustment that reduces the data complexity.
Author Login
Review Login
Editor Login
Reader Login
Editorial Login
Editor-in-Chief Login
