Loading...
Download
More...

Archive

    25 June 2023, Volume 45 Issue 3
    Previous Issue    Next Issue
    Application Prospect and Challenge of Low Orbit Internet System in Navigation Enhancement Service
    ZHANG Zhixue WANG Dexuan MAN Xiaoyuan ZHANG Yize
    2023, 45(3):  266-275.  doi:10.16507/j.issn.1006-6055.2023.05.006
    Asbtract ( 194 )   PDF (1246KB) ( 311 )  
    Related Articles | Metrics
    In recent years, satellite communication technology has developed rapidly. Relying on its advantages of rapid transmission rate and large-scale remote data transmission, as well as the low orbit constellation's characteristics of proximity to the Earth, high signal landing power, low space decay, and rapid geometric change, the low orbit Internet system is expected to make up for the defects of the satellite navigation system in broadcasting rate and signal attenuation to solve the problems of low ground rate of traditional satellite navigation system and long convergence time of real-time PPP. Regarding specific project implementation, the low-orbit constellation can play four roles. First, as a "space-based monitoring station," it can enhance the information of current GNSS. Second, it can be used as a "navigation information source" to realize signal enhancement and information enhancement; Third, the low-orbit constellation can be used as the supplement and backup of the satellite navigation system and maintain the space-time reference independently. Fourth, the integration of satellite communication and navigation services should be realized to realize "integrated communication and navigation" at the user level. By combining the overall design of constellation navigation enhancement in the low-orbit Internet with the current status of GNSS operation services, we can realize complementary advantages and provide broader coverage, higher precision, and more robust time and space services. Firstly, this paper briefly introduces the development status of low-orbit satellites at home and abroad, analyzes the critical technologies of low-orbit satellites in navigation enhancement, especially in broadcast ephemeris parameter design and low-orbit constellation configuration, and focuses on the application and benefits of low-orbit satellites in space-based monitoring information enhancement, signal enhancement and communication integration. The prospects and challenges of applying low-orbit Internet satellite navigation are summarized. 
    Key Technology Development and Application of Pseudolite System
    TANG Wenjie CHEN Junping
    2023, 45(3):  276-284.  doi:10.16507/j.issn.1006-6055.2023.03.002
    Asbtract ( 274 )   PDF (1230KB) ( 453 )  
    Related Articles | Metrics
    The service performance of the Global Navigation Satellite System (GNSS) has significantly decreased in complex environments such as tunnels, indoor and urban canyons. In this challenging environment, pseudolites can be used to generate and transmit signals similar to GNSS systems, providing users with uninterrupted navigation information such as location and speed in GNSS rejection environments. In addition, the pseudolite system can be modulated to be consistent with GNSS, and the user receiver can achieve synchronous reception of pseudolites/GNSS. Through integrated navigation with GNSS and inertial navigation systems, GNSS navigation and positioning enhancement in complex environments can be achieved, which is expected to play an important role in fields such as autonomous driving, indoor navigation, and automatic robots.
    Application Status and Development Trend of Cloud Computing Technology in BDS
    ZHAO Daiyan LIU Lei
    2023, 45(3):  285-293.  doi:10.16507/j.issn.1006-6055.2023.04.001
    Asbtract ( 220 )   PDF (1298KB) ( 177 )  
    Related Articles | Metrics
    Beidou No.3 System is a global navigation satellite system built by China independently. The cloud platform，realizing the unified management, on-demand sharing, and real-time dynamic allocation of software and hardware resources，is essential  to the BDS-3’s ground system. This paper introduces the architecture and process of BDS-3’s cloud platform based on engineering practice and summarizes the representative technical breakthroughs in the cloud platform construction and improvement. The trend of the next generation satellite navigation system is diverse in service types, customized on service information, safe and reliable on capability. The integration between cloud-native technology and the business of navigation ground systems is put forward to improve the efficiency of development and operation; from the perspective of infrastructure structure, it is suggested that the navigation ground cloud be fully autonomous and controllable in stages. Finally, we look forward to the cloud platform architecture of the next-generation navigation ground system. The system architecture, composed of a cloud center, network and terminal, transforms from the construction of independent nodes to the unified construction of all distributed nodes. The navigation ground system will further improve operation and management efficiency and the disaster tolerance and survivability.
    Achievements and Opportunities in the Development of GNSS RTK Positioning Technology
    SONG Wei MAO Wei ZHANG Yize
    2023, 45(3):  294-305.  doi:10.16507/j.issn.1006-6055.2023.03.007
    Asbtract ( 208 )   PDF (1224KB) ( 818 )  
    Related Articles | Metrics
    Real-time Kinematic (RTK) is widely used in surveying and mapping, monitoring, navigation and other aspects due to its advantages of a simple algorithm, fast convergence, high positioning accuracy and outstanding reliability. With the continuous advancement of Global Navigation Satellite System (GNSS) technology, the GNSS RTK positioning mode has made significant progress in theoretical algorithms, engineering applications, and data processing. This paper reviews of RTK positioning technology, focusing on the development history of long-baseline RTK positioning technology, multi-frequency and multi-system, partial ambiguity fixed algorithm, Network RTK Positioning technology and single-frequency RTK algorithm. Also, the critical factors affecting the accuracy and reliability of RTK positioning are summarized. Finally, it discussed the new development opportunities brought by RTK technology with the further construction of GNSS and continuous optimization of sensor technology.
    Review of GNSS Orbits and Clocks Products Combination
    ZHU Hongyu CHEN Junping ZHANG Yize
    2023, 45(3):  306-316.  doi:10.16507/j.issn.1006-6055.2023.04.002
    Asbtract ( 193 )   PDF (1715KB) ( 514 )  
    Related Articles | Metrics
    GNSS(Global Navigation Satellite System) precision orbits and clocks product is the premise of realizing high-precision PPP(Precise Point Position) and the basis of high-precision GNSS application. Therefore, it is of great research significance and application value to develop a combination method of GNSS orbits and clocks product and realize a stable and reliable orbit and clock combined product service. This paper introduces the general situation of the GNSS constellation and IGS(International GNSS Service) service center, combs the functional model of orbit clock combination synthesis, comprehensively analyzes and discusses the progress of GNSS orbit clock combination product synthesis technology, and looks forward to the opportunities brought by existing research on GNSS real-time orbit clock combination synthesis and real-time precise single point positioning.
    Application and Development of High-precision Satellite Laser Ranging in BeiDou Navigation Satellite Systems
    ZHANG Haifeng LONG Mingliang YANG Huafeng DENG Huarong CHENG Zhi’en WU Zhibo MENG Wendong QIN Si LI Pu HUANG Yong ZHANG Zhongping
    2023, 45(3):  317-326.  doi:10.16507/j.issn.1006-6055.2023.05.002
    Asbtract ( 172 )   PDF (2309KB) ( 509 )  
    Related Articles | Metrics
    Satellite laser ranging (SLR) is the most accurate technology in satellite orbit measurement. It is widely used in high-precision orbit determination and satellite orbit accuracy checks for satellites, laser time transfer (LTT), and so on. It is an important part of accurately measuring satellite orbits in navigation systems. This paper describes the SLR system in the Shanghai Astronomical Observatory and the International joint survey of the BeiDou navigation system. The SLR international joint surveys for satellites of BeiDou 3 observation data were obtained from global laser stations in 2023, which provided conditions for the implementation of joint research on global navigation satellite systems. The high repetition frequency of 100kHz SLR technology has been developed, and applied to BeiDou satellites. The standard point data accuracy reaches the level of 100 um, which effectively improves the quality of navigation SLR observation data. At the same time, another application of SLR technology for the BeiDou navigation system was described, including independent satellite orbit determination, Broadcast ephemeris accuracy check, LTT, and so on.
    Progress in the Establishment of the Terrestrial Reference Frame and Consideration of Non-linear Maintenance
    WANG Ruyuan CHEN Junping
    2023, 45(3):  327-337.  doi:10.16507/j.issn.1006-6055.2023.05.005
    Asbtract ( 131 )   PDF (1891KB) ( 350 )  
    Related Articles | Metrics
    In order to a realize millimeter-scale terrestrial reference frame, high-precision non-linear maintenance technology must be gradually improved. Firstly, this paper introduces the progress of the establishment of the terrestrial reference frame including the establishment of the International Terrestrial Reference Frame and the epoch reference frames; Then, the research status of non-linear maintenance technology is described, and two ideas for non-linear maintenance of the terrestrial reference frame are pointed out, including the non-linear change modeling of the reference station and the establishment of the epoch reference frames. At last, the paper puts forward a prospect for the construction of the millimeter-scale terrestrial reference frame, and suggests that the ground monitoring network should be appropriately increased and improved, especially in the underdeveloped areas of the southern hemisphere, and the existing frame should be improved by using longer and broader original data accumulation; Increase the data accumulation of coordinate non-linear motion and geocentric motion, and conduct in-depth analysis, to establish an accurate correction model; Identify the noise factors in the coordinate time series as accurately as possible, and establish a grid noise model to more accurately separate the actual signal and noise.
    Study on Large-scale Application of BeiDou Navigation Satellite System in Mass Market of Smartphone
    WU Mengquan
    2023, 45(3):  338-348.  doi:10.16507/j.issn.1006-6055.2023.04.003
    Asbtract ( 134 )   PDF (1614KB) ( 204 )  
    Related Articles | Metrics
    As BeiDou Navigation Satellite System has entered a new stage of promoting its quality development via application, systematic approaches to applying BeiDou in the mobile market, which is the most sensitive, responsive, flexible, and resilient mass market, hold an essential part in prospering BeiDou industry and national economic development. Through analysis of the large-scale application of BeiDou in the mass market of smartphones from perspectives of the industry chain, value chain, and policy chain, in-depth explorations of prohibiting BeiDou's massive application in smartphones are conducted from the supply side, demand side, and environment side. With a summarization of referable measures from other global navigation satellite systems, especially GPS, policy advice is provided afterward on the large-scale application of BeiDou. Firstly, from the supply side, it is importance to make enterprises play the lead and develop industry via relevant military-to-civilian technologies, which enhances the technical capability of meeting demands. Secondly, from the demand side, it is to develop scenarios with efforts and cultivate world-class product and service providers which dig and upgrade demands. Thirdly, from the environmental side, it is to promote the BeiDou application in smartphones while building the BeiDou brand, which directs consumers' willingness and actions nationwide.
    Review on Optimization Methods of Point Absorption Direct Drive Wave Energy Generator
    LI Yongguo QIN Can ZHENG Dingjian DU Jie ZHU Qiuying
    2023, 45(3):  349-364.  doi:10.16507/j.issn.1006-6055.2022.10.001
    Asbtract ( 130 )   PDF (2334KB) ( 172 )  
    Related Articles | Metrics
    The point absorption wave energy generator has attracted wide attention because of its compact structure, high conversion efficiency, low construction difficulty, high comprehensive performance, low investment cost, not being affected by wave direction, and so on. Point absorption wave energy generators are classified according to wave energy conversion, including mechanical, hydraulic, magnetic fluid, and direct drive. This paper will study the point absorption direct drive wave energy generator. Based on the recent 20 years of research on optimizing wave energy conversion devices at home and abroad, the optimization methods of various functional components in different energy conversion stages are reviewed, including energy capture, energy conversion, and energy output. The future development trend of the point absorption direct drive wave energy generator has been prospected. In addition, the critical problems existing in the wave energy generator are put forward.
    Applications of ROV for Underwater Inspection of Bridge Structures and Review of Its Anti-current Technologies
    SONG Jialing LIU Airong ZHOU Haoxiang FU Jiyang MAO Jihua
    2023, 45(3):  365-382.  doi:10.16507/j.issn.1006-6055.2022.10.006
    Asbtract ( 158 )   PDF (7506KB) ( 346 )  
    Related Articles | Metrics
    With the constant development of the national Infrastructure construction, the focus of the civil industry has been shifting to the detection and maintenance of existing structures. Many bridges have been in service for a long time with the increased traffic volumes. So regular detection is required to ensure the safe operation of those structures. The multifunctional underwater vehicles equipped with cameras, sonars, and other attachments have paid great attention to underwater operations. Also, that provides a critical idea and method for detecting underwater bridge structures. This paper demonstrates the feasibility of a Remotely Operated Vehicle (ROV) in detecting underwater bridge structures, then expounds on typical application scenarios and examples. Furthermore, considering that the weak anti-current of ROV is the main restriction of its popularization and application, the research on how to improve the anti-current of ROV is discussed in detail based on the kinematic force analysis. Finally, the critical guidance of ROV anti-current technologies is concluded, and the research interests of the high-stability ROV have been prospected.
    Research on the Quantification of Science and Technology Financial Policy Text and the Effect of Policy Instrument Combination
    WEN Quan JIA Jingdun QIAO Han LI Xiaoqi WANG Heran WANG Can
    2023, 45(3):  383-397.  doi:10.16507/j.issn.1006-6055.2022.11.001
    Asbtract ( 217 )   PDF (2458KB) ( 246 )  
    Related Articles | Metrics
    Taking the data of China’s science and technology financial Policy at the national level from 1985 to 2019 as an example, based on the review and sorting out the evolution process of science and technology financial policies based on reviewing and combing the evolution process of science and technology financial policy, Nvivo qualitative analysis software is used according to the rooted theory to explore the types of scientific and technological financial policies, the subject of the publication, the types of policy tools and their specific tool content, and refine the scientific and technological financial policy tools into supply type, demand type, and environmental type. In order to deeply analyze the selection and combination effects of various policy tools, the Fuzzy set qualitative comparative analysis method was used to explore the different combinations in the development process of science, technology, and finance in China. The research found that our country's combination of science and technology finance policy tools can be summarized into three types: market-driven, government-market linkage, and policy-led. It also discusses the relationship between the establishment, economic development, and innovation level of the technology and finance policy with the combination of policy instruments. Further, it clarifies the configuration effect of policy instruments for the development strategy of Chinese science and technology finance, which has some reference value in the choice and combination of policy instruments. 
    Analysis on International Experiences in Administration Policy and Mode of Satellite Remote Sensing Resources
    CHEN Fangmiao JIAO Hongzhi HUANG Huiping
    2023, 45(3):  398-406.  doi:10.16507/j.issn.1006-6055.2022.11.007
    Asbtract ( 106 )   PDF (1819KB) ( 137 )  
    Related Articles | Metrics
    The satellite industry started relatively late in China, and there is a gap between China and representative foreign countries in the administration mode of remote sensing data and corresponding policies and regulations. This study summarizes the status of satellite resources and regulations, and analyzes the advantages of the administration mode in several countries/regions(including the United States, Russia, Japan, Canada, France, Germany, India, and ESA): 1)government strongly supports commercial remote sensing industry;2)government and enterprise cooperate in the administration mode;3)mature civil-military integration mode;4)high flexibility and globalization of remote sensing data administration; and 5)efficient industry-university-research cooperation. Finally, this study proposes problem analysis and suggestions based on foreign experiences of the administration method for satellite resources in China.