2022 Vol. 47, No. 10
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.
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.
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".
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.
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.
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
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.
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.
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.
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.
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.
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 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.
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.
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.