查看更多>>摘要：Since the official operation of the BeiDou Global Navigation Satellite System (BDS-3),it has played a vital role in the national economy,national defence and security,and to enhance the people's productivity and life. Based upon the three main characteristics,route design inheritance and development,highly integrated services,and "spiraling" incremental development,this paper introduces the service composition of BeiDou Navigation Satellite System (BDS) and summarizes the evolution of four types of BDS services,that include Positioning,Navigation and Timing (PNT),message communications,navigation augmentation,and international Search and Rescue (SAR). Moreover,the design features and performance of each service are discussed in detail,and the development trend of BDS services is exam-ined in the light of the latest round of changes in the Global Navigation Satellite System (GNSS). Finally,development proposals are proposed,namely,stable operation of the system,enhancement of service performance,and empower-ment through integration of multiple means.
查看更多>>摘要：With the rapid development of intelligent connected vehicles,high-precision 3D navigation has become a key supporting technology. This article conducted a series of drive tests using the high-precision navigation technology of BeiDou and BeiDou+5G hybrid positioning technology,aiming to verify the positioning performance in complex highway traffic environments. The test was conducted on actual roads in Beijing and Hangzhou showed that the po-sitioning accuracy of BeiDou high-precision navigation reached a real-time centimeter level,with a fixed rate of about 95％ and a convergence time of less than 2 s. The elevation accuracy of BeiDou+5G hybrid positioning was better than 0.2 m. Combined with three-dimensional high-precision laser point cloud maps,the overlay verification showed that the model can support three-dimensional lane level navigation,verifying the application potential of BeiDou high-precision positioning and BeiDou+5G hybrid positioning technology in the fields of autonomous driving and intel-ligent connected vehicles.
查看更多>>摘要：In this paper,the technical specifications and characteristics of long-wave infrared payloads are summa-rized,and the main technical indicators are band,resolution,width,etc. The technical characteristics and initial in-orbit application of a new generation of advanced wide-width thermal infrared imager in China are emphatically introduced. Through analysis,it is concluded that the future development of long-wave load should meet the requirements of high radiation resolution,high calibration accuracy,high time resolution and high spatial resolution.
查看更多>>摘要：This paper proposes a multi-UAV cooperative exploration approach based on task-density space partition. In the research of multi-UAV cooperative exploration,it is a prevalent cooperative scheme to control robots to work independently in partitioned spaces. Nonetheless,only considering the position of robots during space partition cannot effectively ensure the overall cooperative efficiency. According to research on task density of current time points and positions of robots during exploration,robots with fewer task points are assigned to work in spaces with more tasks in the rolling horizon optimization planning mode,which can reduce the redundancy of multi-robot cooperative work. Comparative research suggests that the overall exploration efficiency is improved.
查看更多>>摘要：As the core of the rocket system,the performance and quality of rocket engines are of paramount impor-tance. Currently,the production of aerospace model rocket engines does not differentiate the production and selection of motors according to the importance of the mission,which is insufficient to ensure the high reliability requirements of important launch missions. To select rocket engines with better performance quality for more critical launch missions,this paper uses fuzzy comprehensive evaluation and TOPSIS methods based on the test value or assessment informa-tion of evaluation indicators. The method scientifically and accurately ranks the performance quality of rocket engines,choosing the engines with better performance quality for more strategic missions,and providing technical support for national management decisions.
查看更多>>摘要：Mega-constellations of satellites are making a complex network in Low-Earth Orbit (LEO),which presents new legal and technical challenges. The widespread operation of mega-constellations necessitates a special technical and legal regulatory framework that is constantly evolving based on emerging technologies. Although it has not yet been completely established since it is fully dependent on the development of Space Traffic Management (STM),includ-ing the rules on space debris mitigation and collision avoidance systems,cyber security issues,environmental concerns,rules of registration,Radio Frequency Interferences (RFI),Space Surveillance & Tracking (SST),etc.This paper addresses the legal issues of coordinating LEO mega-constellation operations within the framework of STM. The LEO mega-constellations creating the space environment congested necessitates the establishment of STM rules and standards to safeguard the safety,security,and sustainability of outer space activities. To do so,States and the private sector will have to develop effective,safe,and workable mechanisms that will allow space activities in the field of the deployment and operation of satellite constellations while ensuring the sustainability of all space activities on a long-term basis. Moreover,it needs the cooperation of related national and international organizations and other entities,including the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS),its Subcommittees,and Internation Telecommunication Union (ITU),to solve the legal and technical challenges of satellite constellations,especially mega-constellations,through the amendment of the current international legal regime,the implementation of a new international treaty,or the creation of soft law documents.
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