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LEO Enhanced Global Navigation Satellite System(LeGNSS):progress,opportunities,and challenges

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geo-Spatial Information Science 2022年第1期25卷 1-13页

作者： haibo ge Bofeng Li Song Jia Liangwei Nie Tianhao Wu Zhe Yang Jingzhe Shang Yanning Zheng Maorong ge College of Surveying and geo-Informatics Tongji UniversityShanghaiChina Department of geodesy GeoForschungsZentrum(GFZ)TelegrafenbergPotsdamGermany

With the completion of Chinese BeiDou Navigation Satellite System(BDS),the world has begun to enjoy the Positioning,Navigation,and Timing(PNT)services of four Global Navigation Satellite Systems(GNSS).In order to improve the GNSS performance and expand its applications,Low Earth Orbit(LEO)Enhanced Global Navigation Satellite System(LeGNSS)is being vigorously *** with high-,medium-,and low-earth orbit satellites,it can improve GNSS performance in terms of orbit determination,Precise Point Positioning(PPP)convergence time,*** paper comprehensively reviews the current status of LeGNSS,focusing on analyzing its advantages and challenges for precise orbit and clock determination,PPP convergence,earth rotation parameter estimation,and global ionosphere *** to the fast geometric change brought by LEO satellites,LeGNSS is expected to fundamentally solve the problem of the long convergence time of PPP without any *** convergence time can be shortened within 1 minute if appropriate LEO constellations are ***,there are still some issues to overcome,such as the optimization of LEO constellation as well as the real time LEO precise orbit and clock determination.

关键词： LEO Enhanced Global Navigation Satellite System(LeGNSS) orbit determination Precise Point Positioning(PPP) convergence time global ionosphere modeling

Comprehensive assessment of real-time precise products from IGS analysis centers

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Satellite Navigation 2022年第1期3卷 97-113,I0004页

作者： Bofeng Li haibo ge Yuhang Bu Yanning Zheng Leitong Yuan College of Surveying and geoInformatics Tongji UniversityShanghai 200092China

Real-Time Precise Point Positioning(RT-PPP)has been one of the research hotspots in GNSS(Global Navigation Satellite System)community for ***-time precise products of satellite orbits and clocks are the prerequisite for ***,it is of great importance to investigate the current multi-GNSS real-time precise products in State Space Representation(SSR)from diferent analysis *** this article,SSR products from 10 analysis centers are comprehensively evaluated by comparing them with the fnal products and performing the kinematic *** results show that analysis centers CNES(Centre National D’Etudes Spatiales)and WHU(GNSS Research Center of Wuhan University)provide the most complete products with the best *** the accuracy of real-time products for the GNSSs,the accuracies of orbit and clock products are better than 5 cm and 0.15 ns,respectively,for Global Positioning System(GPS),followed by Galileo navigation satellite system(Galileo),BeiDou-3 Navigation Satellite System(BDS-3),GLObal NAvigation Satellite System(GLONASS),and BeiDou-2 Navigation Satellite System(BDS-2).Meanwhile,the results of the RT-PPP with quad-system show that the positioning accuracies are 1.76,1.12 and 2.68 cm in east,north,and up directions,respectively,and the convergence time to 0.1,0.1,0.2 m for corresponding directions is 15.35 min.

关键词： Real-time precise point positioning(RT-PPP) State space representation(SSR) Multi-GNSS Convergence time

Recent advances in directα-C(sp^(3))-H bond functionalization of thioethers

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Green Synthesis and Catalysis 2022年第3期3卷 203-211页

作者： Long Tang Qingyue Hu Ke Yang Mazen Elsaid Chong Liu haibo ge Institute of Chemical Industry of Forest Products Chinese Academy of ForestryNanjing 210042China Jiangsu Key Laboratory of Advanced Catalytic Materials&Technology School of Petrochemical EngineeringChangzhou UniversityChangzhou 213164China Department of Chemistry and Biochemistry Texas Tech UniversityLubbock TX 79409USA

Thioether skeletons are widely present in drugs,natural products,functional materials,and life *** the past decade,the selective C–H functionalization of thioethers has been extensively studied to construct novel thioether *** mini-review systematically introduces the recent advances in the field of the directα-C(sp^(3))-H functionalization of thioethers.

关键词： Thioether C(sp^(3))-H bond Functionalization Photochemistry Electrochemistry Organic synthesis

Prototype of Real-time Orbit Service for LEO Navigation Satellite System

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Prototype of Real-time Orbit Service for LEO Navigation Sate...

Assessment of solar radiation pressure models for BDS-3 MEO navigation satellites

第十四届中国卫星导航年会

作者： Guanlong Meng haibo ge Bofeng Li College of Surveying and geo-informatics Tongji University

With continuous deployment of Low Earth Orbit(LEO) satellites and development of inter-satellite links, LEO enhanced Global Navigation Satellite System(LeGNSS) brings new opportunities for future high-precision positioning, navigation, and timing(PNT) services. Real-time precise LEO orbit is the prerequisite for real-time precise positioning. In order to provide precise real-time LEO orbit and guarantee the normal operation of LeGNSS, a prototype of real-time orbit service for LEO navigation satellite system is proposed. We evaluate the accuracy of LEO orbit, and demonstrate the system infrastructure and working principle. In addition, two real-time LEO orbit broadcasting methods are designed:(1) using LEO orbit determined by RTS products as the fitting part to predict orbit, the prediction part is fitted by ephemeris parameters, which are injected into LEO and broadcasted to users.(2) differences between LEO orbits obtained by RTS products and the broadcast ephemeris are used to generate orbit corrections and broadcasted to *** show that LEO near-real-time orbit achieves centimeter-level accuracy,and the fitting errors of broadcast ephemeris are smaller than 10 cm in 20-minute fitting arc. Moreover, the LEO broadcast ephemeris would obtain decimeter-level accuracy orbit, while the orbit corrections method would provide users with real-time centimeter-level LEO orbit.

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Assessment of solar radiation pressure models for BDS-3 MEO ...

第十四届中国卫星导航年会

作者： Leitong Yuan Bofeng Li Weiguang Gao haibo ge College of Surveying and geo-Informatics Tongji University Beijing Institute of Tracking and Telecommunication Technology

Precise orbit products of BeiDou Navigation Satellite System(BDS)are the primary prerequisite to provide high-quality positioning, navigation and timing services. As the dominating satellite type in BDS-3 constellation, the orbit accuracy of Medium Earth Orbit(MEO) satellite mainly depends on geometric observation conditions and the quality of dynamic models. In recent years, the growing number of global BDS monitoring stations greatly enhance the geometric pattern for BDS-3 MEO satellites. However, solar radiation pressure(SRP) of BDS-3 MEO satellites is still under investigation and the SRP models adopted by analysis centers in the International GNSS Service(IGS) are different from each other. Based on International GNSS Monitoring and Assessment System(iGMAS) BeiDou analysis center of Tongji University,this paper comprehensively evaluates six SRP models(e.g., ECOM1, ECOM2,ECOM1 with a prior Box-wing model, ECOM2 with a prior Box-wing model,ECOM1 with an empirical force model, ECOM2 with an empirical force model) that commonly used for BDS-3 MEO satellites. The results indicate that compared with ECOM1 model, ECOM2 model can reduce orbit overlap error by 5.02% when satellites are out of earth eclipse. Moreover, ECOM2 model can effectively reduce the orbit overlap error in spite of a low solar elevation *** for satellite laser ranging residuals of BeiDou-3 MEO satellites, ECOM1model with an empirical force model performs better. The average orbit bias in radial direction is 0.63～2.51cm and the standard deviation is 2.68～3.16cm,which is decreased by 7.76%～26.97% comparing with other five ***, the orbit products resolved by this paper is better than orbit products provided by GFZ and WUM in radial direction.

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边缘计算中多服务器协同任务缓存策略

计算机工程与应用 2023年第20期59卷 245-253页

作者：马世雄葛海波宋兴西安邮电大学电子工程学院西安710121

针对边缘服务器有限的计算、存储资源与大量用户任务请求之间的矛盾,设计了基于多服务器协同的边缘计算任务缓存网络架构,该架构中边缘服务器可以在内存中缓存并执行用户任务,未缓存的任务放在云端执行。结合用户任务请求时变和邻近区... 详细信息

针对边缘服务器有限的计算、存储资源与大量用户任务请求之间的矛盾,设计了基于多服务器协同的边缘计算任务缓存网络架构,该架构中边缘服务器可以在内存中缓存并执行用户任务,未缓存的任务放在云端执行。结合用户任务请求时变和邻近区域用户更倾向于请求相似任务的特点,提出一种基于改进Soft Actor-Critic的多服务器协同任务缓存算法(MSAC)。该算法以最小化用户平均任务执行时延为目标,为避免反复选择同一动作而收敛于局部最优,引入最大熵模型来鼓励边缘服务器探索最优动作。通过设计经验共享机制,收集并学习本地边缘服务器和相邻服务器的经验以优化任务缓存策略。仿真结果表明,与最高流行度算法、独立SAC算法、DQN算法、遗传算法相比,所提出的MSAC算法在降低用户任务平均执行时延方面的效果最好。

关键词：边缘计算任务缓存多服务器协作深度强化学习

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利用多基数系统的高效椭圆曲线多标量乘算法

计算机工程 2021年第2期47卷 182-187页

作者：尤文珠葛海波西安邮电大学电子工程学院西安710121

针对椭圆曲线密码体制中标量乘与多标量乘运算耗时过长的问题,设计以2、3、7为基元的多基整数表示方法,并结合多基数系统(MBNS)及滑动窗口算法,提出基于MBNS滑动窗口(Sliding MBNS)和交错MBNS滑动窗口(I-MBNS)的多标量乘快速算法,分析... 详细信息

针对椭圆曲线密码体制中标量乘与多标量乘运算耗时过长的问题,设计以2、3、7为基元的多基整数表示方法,并结合多基数系统(MBNS)及滑动窗口算法,提出基于MBNS滑动窗口(Sliding MBNS)和交错MBNS滑动窗口(I-MBNS)的多标量乘快速算法,分析并比较两种多标量乘快速算法在二元域和素域及不同窗口宽度下的平均运算量。实验结果表明,与Shamir和交错非邻接形式算法相比,Sliding MBNS和I-MBNS算法在标量长度为160 bit的二元域上的平均运算量分别减少了10.00%、1.69%和13.00%、4.97%,具有更低的运算复杂度和更高的标量乘算法效率。

关键词：多标量乘椭圆曲线密码多基数系统公钥密码体制滑动窗口算法

Multiphysics simulation and optimization of the in-situ beneficiation process of ilmenite minerals from lunar regolith

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Science China Earth Sciences 2025年第1期68卷 195-207页

作者： Peng ZHANG Xin LIU Guanghui LIU Wei DAI Hanzhe YANG haibo ZHENG Zhi WANG Ran NIU Yifan BAI Yang ZHANG Chengbao LIU ge YANG Junwei YANG Guang ZHANG Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing Hegong Simulation Co. Ltd

The exploration and utilization of lunar resources have become the major objectives of future lunar exploration missions. The classified collection and processing of lunar minerals is the basic prerequisite for the in-situ exploration and utilization of lunar resources. In this study, we propose a scheme for in-situ separation of magnetic minerals from lunar soils using the dry magnetic separation method. The scheme can realize the purpose of separating magnetic minerals from lunar regolith by altering the motion trajectory of lunar regolith particles with different magnetic properties. Detailed modeling of the dry magnetic separation device is conducted, and the three-dimensional distribution of magnetic parameters is calculated and analyzed. Based on the characterization and analysis of the Chang E-5's samples, the morphologies and physical parameters of lunar regolith particles are modeled and simulated. A discrete element simulation of the motion process of lunar regolith particles under multi-physical field conditions is performed, and the influences of key parameters on the beneficiation performance of lunar magnetic minerals are investigated. Our results indicate that optimal separation and beneficiation of lunar regolith particles can be achieved under specific conditions of magnetic field strength and drum speed. Additionally, we analyze the effects of lunar weak gravity conditions and the charged nature of lunar particles on the beneficiation process, showing that these factors can obviously enhance the beneficiation process of lunar ilmenites. This study demonstrates the feasibility of using the dry magnetic separation method for the beneficiation of magnetic minerals from lunar regolith, providing a theoretical basis for the scientific tasks of collecting, processing, and utilizing lunar mineral resources.

关键词： Lunar regolith In-situ resource utilization Magnetic separation Classified sampling

无电离层组合、Uofc和非组合精密单点定位观测模型比较

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测绘学报 2015年第7期44卷 734-740页

作者：李博峰葛海波沈云中同济大学测绘与地理信息学院上海200092

GNSS精密单点定位技术因其只采用单台接收机就能获得高精度的定位结果而成为近年来的研究热点。精密单点定位通常采用3种模型:无电离层组合模型、Uofc模型与非组合模型。本文从模糊度固定的角度详细论述了这3种模型的相互关系,公式推导... 详细信息

GNSS精密单点定位技术因其只采用单台接收机就能获得高精度的定位结果而成为近年来的研究热点。精密单点定位通常采用3种模型:无电离层组合模型、Uofc模型与非组合模型。本文从模糊度固定的角度详细论述了这3种模型的相互关系,公式推导证明了非组合模型与Uofc模型等价,且都优于无电离层组合模型;与采用等价性原理消去电离层延迟的Uofc模型相比,非组合模型将电离层延迟作为参数求解,能为用户提供附加电离层先验约束的条件,从而方便地转换为电离层加权模型。在固定宽巷模糊度的情况下,采用模糊度精度因子(ADOP)对模糊度的固定效率进行了分析,验证了Uofc模型相对于无电离层组合模型具有噪声小、不损失原始观测信息等优点。而附电离层约束的非组合模型在高精度先验电离层信息约束下能有效提高模糊度固定效率。

关键词：精密单点定位PPP 定位模型等价性原理模糊度固定模糊度精度因子