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Dual-assisted high-precision tracking technique for wideband multiplexed signals in new generation GNSS

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satellite Navigation 2024年第1期5卷 52-73页

作者： Yunhan Qi Zheng Yao Mingquan Lu department of Electronic Engineering Tsinghua UniversityBeijing100084China Beijing National Research center for Information Science and technology Beijing100084China

With the evolution of Global Navigation satellite System(GNSS),new generation GNSS signals have adopted the dual-frequency multiplexing modulation techniques,which jointly modulate multiple signals located on multiple sub-frequencies into a Wideband Multiplexed Signal(WMS).Although WMSs were proposed initially to reduce the complexity of satellite transmitters and improve the transmission efficiency of signals,their multi-component structures and wide root mean square bandwidths introduced by high-frequency subcarriers also provide the possibility to improve the GNSS ranging ***,this paper proposes a Dual-assisted Multi-component Tracking(DMT)technique,which can not only fully use high-frequency subcarriers in WMSs,but also effectively track carrier,subcarrier,and code by jointly utilizing all components in *** this paper,the tracking and ranging performances of DMT are comprehensively analyzed theoretically and by simulation and real *** results show that compared with existing WMS tracking methods,DMT can achieve tracking results with lower tracking jitters and ranging results with higher precision,providing a highly advantageous solution for new generation GNSS signal processing.

关键词： Wideband multiplexed signal Dual-assisted Multi-component High precision tracking

Improved LS+MAR hybrid method to UT1-UTC ultra-short-term prediction by using first-order-difference UT1-UTC

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Geodesy and Geodynamics 2024年第4期15卷 379-385页

作者： Fei Ye Yunbin Yuan BeiDou High-precision satellite Navigation and Location Service Hunan Engineering Research center Hunan Institute of Geomatics Sciences and TechnologyChangsha410007China State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan430077China HNCORS Data center Hunan Institute of Geomatics Sciences and TechnologyChangsha 410007China

Accurate ultra-short-term prediction of the Earth rotation parameters(ERP)holds paramount impor-tance for real-time applications,particularly in reference frame *** them,diurnal rota-tion(UT1-UTC)which cannot be directly estimated through Global Navigation satellite System(GNSS)techniques,significantly affects the rapid and ultra-rapid orbit determination of GNsS ***-ently,the traditional LS(least squares)+AR(autoregressive)and LS+MAR(multivariate autoregressive)hybrid methods stand as primary approaches for UT1-UTC ultra-short-term predictions(1-10 days).The LS+MAR hybrid method relies on the UT1-UTC and LOD(length of day)***,the correlation between LOD and first-order-difference UT1-UTC is stronger than that between LOD and *** light of this,and with the aid of the first-order-difference UT1-UTC,we propose an enhanced LS+MAR hybrid method to UT1-UTC ultra-short-term *** using the UT1-UTC and LOD data series of the IERS(International Earth Rotation and Reference Systems Service)EOP 14 C04 product,we conducted a thorough analysis and evaluation of the improved method's prediction performance compared to the traditional LS+AR and LS+MAR hybrid *** to the numerical results over more than 210 days,they demonstrate that,when considering the correlation information between the LoD and the first-order-difference UT1-UTC,the mean absolute errors(MAEs)of the improved LS+MAR hybrid method range from 21 to 934μs in 1-10 days *** comparison to the traditional LS+AR hybrid method,the MAEs show a reduction of 7-53μs in 1-10 days predictions,with corresponding improvement percentages ranging from 1 to 28%.Similarly,when compared to the traditional LS+MAR hybrid method,the MAEs have a reduction of 5-42μs in 1-10 days predictions,with corresponding improvement percentages ranging from 4-20%.Additionally,when aided by GNSS-derived LOD data series,the MAEs of improved LS+MAR hybrid method experience further

关键词： UT1-UTCultra-short-termprediction Rapidandultra-rapidproducts LS+AR and LS+MAR Correlation First-order-differenceUT1-UTC

The First Global Map of Atmospheric Ammonia(NH_(3)) as Observed by the HIRAS/FY-3D satellite

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Advances in Atmospheric Sciences 2024年第3期41卷 379-390页

作者： Minqiang ZHOU Zhili DENG Charles ROBERT Xingying ZHANG Lu ZHANG Yapeng WANG Chengli QI Pucai WANG Martine De MAZIÈRE Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China Royal Belgian Institute for Space Aeronomy(BIRA-IASB) Brussels 1180Belgium National satellite Meteorology center China Meteorological AdministrationBeijing 100081China department of Science&technology and Climate Change China Meteorological AdministrationBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China

Atmospheric ammonia(NH_(3)) is a chemically active trace gas that plays an important role in the atmospheric environment and climate change. satellite remote sensing is a powerful technique to monitor NH_(3) concentration based on the absorption lines of NH_(3) in the thermal infrared region. In this study, we establish a retrieval algorithm to derive the NH_(3)column from the Hyperspectral Infrared Atmospheric Sounder(HIRAS) onboard the Chinese Feng Yun(FY)-3D satellite and present the first atmospheric NH_(3) column global map observed by the HIRAS instrument. The HIRAS observations can well capture NH_(3) hotspots around the world, e.g., India, West Africa, and East china, where large NH_(3) emissions exist. The HIRAS NH_(3) columns are also compared to the space-based Infrared Atmospheric Sounding Interferometer(IASI)measurements, and we find that the two instruments observe a consistent NH_(3) global distribution, with correlation coefficient(R) values of 0.28–0.73. Finally, some remaining issues about the HIRAS NH_(3) retrieval are discussed.

关键词： ammonia HIRAS/FY-3D satellite thermal-infrared observation remote sensing optimal estimation method

Global hybrid simulations of soft X-ray emissions in the Earth’s magnetosheath

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Earth and Planetary Physics 2024年第1期8卷 47-58页

作者： Jin Guo TianRan Sun San Lu QuanMing Lu Yu Lin XueYi Wang Chi Wang RongSheng Wang Kai Huang School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China CAS center for Excellence in Comparative Planetology/CAS Key Lab of Geospace Environment University of Science and Technology of ChinaHefei 230026China Collaborative Innovation center of Astronautical Science and technology Harbin 150001China National Space Science center Chinese Academy of SciencesBeijing 100190China Physics department Auburn UniversityAuburnALUSA

Earth’s magnetopause is a thin boundary separating the shocked solar wind plasma from the magnetospheric plasmas,and it is also the boundary of the solar wind energy transport to the *** X-ray imaging allows investigation of the large-scale magnetopause by providing a two-dimensional(2-D)global view from a *** performing 3-D global hybrid-particle-in-cell(hybrid-PIC)simulations,we obtain soft X-ray images of Earth’s magnetopause under different solar wind conditions,such as different plasma densities and directions of the southward interplanetary magnetic *** all cases,magnetic reconnection occurs at low latitude *** soft X-ray images observed by a hypothetical satellite are shown,with all of the following identified:the boundary of the magnetopause,the cusps,and the *** X-ray emissivity in the magnetosheath is characterized by large amplitude fluctuations(up to 160%);however,the maximum line-of-sight-integrated X-ray intensity matches the tangent directions of the magnetopause well,indicating that these fluctuations have limited impact on identifying the magnetopause boundary in the X-ray ***,the magnetopause boundary can be identified using multiple viewing *** also find that solar wind conditions have little effect on the magnetopause *** Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will provide X-ray images of the magnetopause for the first time,and our global hybrid-PIC simulation results can help better understand the 2-D X-ray images of the magnetopause from a 3-D perspective,with particle kinetic effects considered.

关键词： magnetopause X-ray emissivity X-ray imaging SMILE global hybrid-PIC simulation

Mega-Constellations Based TT&C Resource Sharing: Keep Reliable Aeronautical Communication in an Emergency

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china Communications 2024年第2期21卷 1-16页

作者： Haoran Xie Yafeng Zhan Jianhua Lu department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research center for Information Science and technology Tsinghua UniversityBeijing 100084China

With the development of the transportation industry, the effective guidance of aircraft in an emergency to prevent catastrophic accidents remains one of the top safety concerns. Undoubtedly, operational status data of the aircraft play an important role in the judgment and command of the Operational Control center(OCC). However, how to transmit various operational status data from abnormal aircraft back to the OCC in an emergency is still an open problem. In this paper, we propose a novel Telemetry, Tracking,and Command(TT&C) architecture named Collaborative TT&C(CoTT&C) based on mega-constellation to solve such a problem. CoTT&C allows each satellite to help the abnormal aircraft by sharing TT&C resources when needed, realizing real-time and reliable aeronautical communication in an emergency. Specifically, we design a dynamic resource sharing mechanism for CoTT&C and model the mechanism as a single-leader-multi-follower Stackelberg game. Further, we give an unique Nash Equilibrium(NE) of the game as a closed form. Simulation results demonstrate that the proposed resource sharing mechanism is effective, incentive compatible, fair, and reciprocal. We hope that our findings can shed some light for future research on aeronautical communications in an emergency.

关键词： aeronautical emergency communication mega-constellation networked TT&C resource allocation stackelberg game

An Industrial Control System Data Shunt and One-way Transmission Security Model

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An Industrial Control System Data Shunt and One-way Transmis...

Multi-scenario Simulation of the Impact of Land Use Change on the Ecosystem Service Value in the Suzhou-Wuxi-Changzhou Metropolitan Area,china

第36届中国控制会议

作者： YAO Pei-song XU Fei-ran LI Jie china xichang satellite launch center technology department

ISBN: (纸本)9781538629185

The existing industrial control systems（ICS） security solutions cannot be directly used for secret or high sensitive areas,for lack of mature theory support and difficult engineering *** this paper,data shunt and one-way transmission security model based on defense-in-depth framework is put forward to ensure the production area availability as the primary *** key signals and instructions of production area are copied *** copy is used to production and the other one for cyber after photoelectric conversion device of isolation ***-way transmission,response speed;data accuracy and product procurement are *** results show that the circuit characteristics of one-way information transmission can prevent outside attack based on general industry *** model has no influence on the transmission of the signals and instructions of production *** time delay and the loss of data accuracy caused by model meet the actual *** components of mode are general and easy to purchase and be used in the practical *** model can be extended to test various emerging ICS security solutions based on defense-in-depth.

关键词： Network physical isolation defense-in-depth optical isolator intrinsically safe isolator shunt and one-way transmission

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Chinese Geographical Science 2024年第1期34卷 79-92页

作者： WANG Bin HU Chunguang ZHANG Yushuo department of Tourism Management Soochow UniversitySuzhou215123China Academy of Culture and Tourism Research Soochow UniversitySuzhou215123China School of Architecture and Urban Planning Huazhong University of Science and TechnologyWuhan430074China Hubei Engineering and technology Research center of Urbanization Wuhan430074China Faculty of Culture Tourism Shanxi University of Finance and EconomicsTaiyuan030006China

As the most economically developed metropolitan area in china’s Yangtze River Delta,the rapid changing land use patterns of Suzhou-Wuxi-Changzhou(Su-Xi-Chang) metropolitan area have profound impacts on the ecosystem service value(ESV).Based on the patterns of land use change and the ESV change in Su-Xi-Chang metropolitan area from 2000 to 2020,we set up four scenarios:natural development scenario,urban development scenario,arable land protection scenario and ecological protection scenario,and simulated the impact of land use changes on the ESV in these *** results showed that:1) the area of built-up land in the Su-xichang metropolitan area increased significantly from 2000 to 2020,and the area of other types of land *** land underwent the highest transfer-out area,and was primarily converted into built-up *** total ESV of Su-Xi-Chang metropolitan area increased initially then declined from 2000–2020,and the value of almost all individual ecosystem services decreased.2) Population density,GDP per area,night lighting intensity,and road network density can negatively impact the ESV.3) The total ESV loss under the natural development and urban development scenarios was high,and the expansion of the built-up land and the drastic shrinkage of the arable land contributed to the ESV decline under both *** total ESV under arable land protection and ecological protection scenarios increases,and therefore these scenarios are suitable for future land use optimization in *** study could provide a certain reference for land use planning and allocation,and offer guidance for the rational allocation of land resources.

关键词： multiple scenarios land use simulation ecosystem service value(ESV) Patch-Generating Land Use Simulation(PLUS)model Suzhou-Wuxi-Changzhou(Su-Xi-Chang)metropolitan area

A Numerical Calculation Algorithm of the Inclination Function Based on the Representation of SO(3) Group

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 137-148页

作者： Yu-xiao Wei Wen-lin Tang department of Geophysics School of Geology Engineering and GeomaticsChang’An UniversityXi’an710064China Key Laboratory of Electronics and Information technology for Space Systems National Space Science CenterChinese Academy of SciencesBeijing100190China

In the determination of the Earth gravity field in satellite geodesy, the inclination functions represent the projection of data observed along the orbital plane of a satellite orbit into the sphere in the terrestial reference frame. The inclination functions in this work is studied from a group theoretical perspective. The inclination functions are proved to generate a representation of the SO(3) group. An orthogonal relation of the inclination functions is derived and some recurrence relations for the inclination functions are given, based on which an algorithm to calculate the inclination functions is proposed.

关键词： SO(3)group inclination function satellite geodesy representation of SO(3)

Damage and fracture model for eutectic composite ceramics

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Acta Mechanica Sinica 2019年第1期35卷 190-200,I0006页

作者： Jinfeng Yu Xinhua Ni Xiequan Liu Yunwei Fu Zhihong Du department of Vehicle and Electric Engineering Army Engineering UniversityShijiazhuang 050003China Army Infantry College Nanchang 330000China xichang satellite launch center Xichang 615000China

Study of damage and fracture models to analyze the fracture mechanism of eutectic composite ceramics is of considerable importance because no accurate fracture models are available for these materials. Eutectic composite ceramics are composed of microcells with random direction. We present herein a model that predicts the damage and fracture of eutectic composite ceramics based on analysis of defect stability and the damage localization band. Firstly, given the microstructure of eutectic composite ceramics, a mesodomain and a microcell model are constructed. The local stress field in the mesodomain is then analyzed based on the interaction direct derivative estimate. Secondly, the stability of a defect around particles in a microcell is analyzed, and the stress intensity factor of an annular defect under the applied stress field and the residual stress field in the particle are calculated. The stress intensity factor of a defect is controlled by the residual stress when the defect extension is small. However, it is controlled by the applied stress when the defect extension is large. Finally, a model for the damage localization band at the crack tip is constructed based on the Dugdale-Barenblatt model. The residual intensity is the important factor affecting the length of the damage localization band. When the damage variables reach their largest value, the residual in ten sity and the length of the damage localization band attain their minimum value. This work provides the theoretical basis for further study of the damage mechanics of eutectic composite ceramics and guides the engineering applications of these materials.

关键词： Microcell Interaction direct derivative estimate Defect stability Damage localization band