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Autonomous navigation method of satellite constellation based on adaptive forgetting factors

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Chinese Journal of Aeronautics 2024年第7期37卷 317-332页

作者： Dong WANG Jing YANG kai xiong School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control EngineeringBeijing 100094China

To address the problem that model uncertainty and unknown time-varying system noise hinder the filtering accuracy of the autonomous navigation system of satellite constellation,an autonomous navigation method of satellite constellation based on the Unscented Kalman Filter with Adaptive Forgetting Factors(UKF-AFF)is *** process noise covariance matrix is estimated online with the strategy that combines covariance matching and adaptive adjustment of forgetting *** adaptive adjustment coefficient based on squared Mahalanobis distance of state residual is employed to achieve online regulation of forgetting factors,equipping this method with more *** intersatellite direction vector obtained from photographic observations is introduced to determine the constellation satellite orbit together with the distance measurement to avoid rank deficiency *** that the number of available measurements varies online with intersatellite visibility in practical applications such as time-varying constellation configurations,the smooth covariance matrix of state correction determined by innovation and gain is adopted and constructed *** analysis of the proposed method is also *** effectiveness of the proposed method is verified by the Monte Carlo simulation and comparison *** estimation accuracy of constellation position and velocity of UKF-AFF is improved by 30%and 44%respectively compared to those of the extended Kalman filter,and the method proposed is also better than other several adaptive filtering methods in the presence of significant model uncertainty.

关键词： Constellation autonomous navigation Unscented Kalman filter Adaptive forgetting factor Model uncertainty Stability analysis

Low-frequency Periodic Error Identification and Compensation for Star Tracker Attitude Measurement

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Chinese Journal of Aeronautics 2012年第4期25卷 615-621页

作者： WANG Jiongqi xiong kai ZHOU Haiyin Department of Mathematics and System Science National University of Defense Technology Changsha 410073 China National Laboratory of Space Intelligent Control Beijing 100048 China

The low-frequency periodic error of star tracker is one of the most critical problems for high-accuracy satellite attitude *** this paper an approach is proposed to identify and compensate the low-frequency periodic error for star tracker in attitude *** analytical expression between the estimated gyro drift and the low-frequency periodic error of star tracker is derived *** then the low-frequency periodic error,which can be expressed by Fourier series,is identified by the frequency spectrum of the estimated gyro drift according to the solution of the first ***,the compensated model of the low-frequency periodic error is established based on the identified parameters to improve the attitude determination ***,promising simulated experimental results demonstrate the validity and effectiveness of the proposed *** periodic error for attitude determination is eliminated basically and the estimation precision is improved greatly.

关键词： star trackers attitude determination low-frequency periodic error gyro drift precision analysis

On Rough Marcinkiewicz Integrals along Surfaces

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Acta Mathematica Sinica,English Series 2010年第4期26卷 717-730页

作者： Huo xiong WU Jian kai XU School of Mathematical Sciences Xiamen University Xiamen 361005 P. R. China

In this paper, the authors establish the LP-mapping properties of certain classes of Marcinkiewicz integral operators along surfaces with rough kernels. The results in this paper essentially extend as well as improve ... 详细信息

关键词： Marcinkiewicz integrals surfaces maximal operator Hardy space rough kernel

A Machine-Learning Based Time Constrained Resource Allocation Scheme for Vehicular Fog Computing

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China Communications 2019年第11期16卷 29-41页

作者： Xiaosha Chen Supeng Leng Ke Zhang kai xiong School of Information and Communication Engineering University of Electronic Science and Technology of China

Through integrating advanced communication and data processing technologies into smart vehicles and roadside infrastructures,the Intelligent Transportation System(ITS)has evolved as a promising paradigm for improving safety,efficiency of the transportation ***,the strict delay requirement of the safety-related applications is still a great challenge for the ITS,especially in dense traffic *** this paper,we introduce the metric called Perception-Reaction Time(PRT),which reflects the time consumption of safety-related applications and is closely related to road efficiency and *** the integration of the incorporating information-centric networking technology and the fog virtualization approach,we propose a novel fog resource scheduling mechanism to minimize the ***,we adopt a deep reinforcement learning approach to design an on-line optimal resource allocation *** results demonstrate that our proposed schemes is able to reduce about 70%of the RPT compared with the traditional approach.

关键词： deep reinforcement learning information-centric networking intelligent transport system perception-reaction time resource allocation vehicular fog

Recent active thermal management technologies for the development of energy-optimized aerospace vehicles in China

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Chinese Journal of Aeronautics 2021年第2期34卷 1-27页

作者： Jixiang WANG Yunze LI Xiangdong LIU Chaoqun SHEN Hongsheng ZHANG kai xiong College of Electrical Energyand Power EngineeringYangzhou UniversityYangzhou 225009China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China Institute of Engineering Thermophysics North China University of Water Conservancy and Electrical PowerZhengzhou 450045China HiWING General Aviation Equipment Corporation Limited Beijing 100074China School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen Graduate SchoolShenzhen 518117China

Recently, the development of modern vehicles has brought about aggressive integration and miniaturization of on-board electrical and electronic devices. It will lead to exponential growth in both the overall waste heat and heat flux to be dissipated to maintain the devices within a safe temperature range. However, both the total heat sinks aboard and the cooling capacity of currently utilized thermal control strategy are severely limited, which threatens the lifetime of the on-board equipment and even the entire flight system and shrink the vehicle’s flight time and range. Facing these thermal challenges, the USA proposed the program of "INVENT" to maximize utilities of the available heat sinks and enhance the cooling ability of thermal control strategies. Following the efforts done by the USA researchers, scientists in China fought their ways to develop thermal management technologies for Chinese advanced energy-optimized airplanes and spacecraft. This paper elaborates the available on-board heat sinks and aerospace thermal management systems using both active and passive technologies not confined to the technology in China. Subsequently, active thermal management technologies in China including fuel thermal management system, environment control system, non-fuel liquid cooling strategy are reviewed. At last, space thermal control technologies used in Chinese Space Station and Chang’e-3 and to be used in Chang’e-5 are *** issues to be solved are also identified, which could facilitate the development of aerospace thermal control techniques across the world.

关键词： Aerospace engineering Efficiency promotion Fluid dynamics Heat and mass transfer Thermal management

Hawking Radiation from Horizons of Reissner-Nordstrm de Sitter Black Hole with a Global Monopole via Anomalies

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Communications in Theoretical Physics 2008年第8期50卷 537-540页

作者： CHEN Shi-Wu LIU xiong-Wei LIN kai ZENG Xiao-xiong YANG Shu-Zheng Institute of Theoretical Physics China West Normal University Nanchong 637002 China

Hawking radiation from cosmological horizon and event horizon of the Reissner-Nordstrom de Sitter black hole with a global monopole is studied via a new method that was propounded by Robinson and Wilzek and elaborated by Banerjee and Kulkarni. The results show that the gauge current and energy-momentum tensor fluxes, which required keeping gauge covariance and general coordinate invariance at the quantum level in the effective field theory, are exactly equivalent to those of Hawking radiation from the event horizon and the cosmological horizon, respectively.

关键词： covariant anomaly Hawking radiation Reissner-Nordstrom de sitter black hole global monopole

Facile preparation of Nb_(2)O_(5) microspheres and their excellent electrochemical performance in aqueous zinc-ion hybrid supercapacitors

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Rare Metals 2022年第9期41卷 3129-3141页

作者： Si-Jia Zhang Han Chen Yi-Xue Xu Chang-Sheng An kai-xiong Xiang School of Materials and Advanced Manufacturing Liling Ceramic InstituteHunan University of TechnologyZhuzhou412007China Hunan Institute of Science and Technology Yueyang414000China Hunan Key Laboratory of Applied Environmental Photocatalysis Changsha UniversityChangsha410022China

The aqueous solution-based zinc-ion hybrid supercapacitors(ZHSCs)have attracted immense attention as they are characterized by high power and energy *** materials with high performance should be developed for ZHSCs to resolve power imbalances between capacitor-and battery-type electrode *** address this issue,Nb_(2)O_(5) microspheres(with the structure like sweet dumplings with exposed stuffing)were produced following a hydrothermal process which was followed by a high-temperature calcination *** specific capacity of the as-synthesized Nb_(2)O_(5) microspheres was up to 324 F·g^(-1) when the current density was 0.1 A·g^(-1),and the long-term capacity retention was 85%at the end of 5000 *** results revealed that the nanospheres could be used as battery-type electrode materials for the fabrication of ***_(2)O_(5)//AC ZHSCs were fabricated with Nb_(2)O_(5) microspheres as the negative electrode materials,and activated carbon(AC)was used as the positive electrode *** a result,a specific capacity of 108 F·g^(-1) was achieved when the current density was 0.1 A·g^(-1).The power density was high(8020 W·kg^(-1))at 28 Wh·kg^(-1),and the energy density was high(60 Wh·kg^(-1))at 100 W·kg^(-1).The structurally novel Nb_(2)O_(5) microspheres can be potentially used for the development of the next-generation ZHSCs that exhibit excellent performance.

关键词： Hydrothermal Microspheres Nb_(2)O_(5) Zincion hybrid supercapacitors(ZHSCs) Fast kinetics

Three-dimensional hierarchically porous nitrogen-doped carbon from water hyacinth as selenium host for high-performance lithium-selenium batteries

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Rare Metals 2022年第10期41卷 3432-3445页

作者： Wei-Na Deng Yan-Hua Li Di-Fa Xu Wei Zhou kai-xiong Xiang Han Chen Hunan Key of Laboratory of Applied Environmental Photocatalysis Changsha UniversityChangsha410022China School of Metallurgy and Materials Engineering Hunan University of TechnologyZhuzhou412007China

Hierarchically porous nitrogen-doped carbon(HPNC) with interconnected micro-,meso-,and macropores was generated from KOH and urea etching as a carbon scaffold to infuse *** this structure,micropores confine Se as single-chain molecules,preventing the generation of higher-order polyselenides,the mesopores provide effective pathways for electrolyte diffusion and ion transport and offer sufficient void space to accommodate the volume change of Se upon lithiation/delithiation,and the doped nitrogen improves the electrical conductivity of HPNC and increases the utilization of *** applied as a scaffold for Se in a lithium-selenium battery,the Se/HPNC cathode with a large Se content of 67.6 wt% maintains a high discharge capacity of 410 mAh·g^(-1) at the 500 th cycle at1.0 C,and it demonstrates a discharge capacity as high as371 mAh·g^(-1) even at a high current density of 5.0 ***,when the current density returns to 0.2 C,the discharge capacity recovers to 527 mAh·g^(-1) with a capacity retention rate of 90.5% for the first 0.2 C,indicating the excellent structural stability of *** has significant potential for application in energy storage systems.

关键词： Hierarchically porous carbon Nitrogen-doped carbon Li-Se batteries Electrochemical performances

Stacking fault,dislocation dissociation,and twinning in Pt_(3) Hf compounds:a DFT study

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Rare Metals 2021年第4期40卷 1020-1030页

作者： Shun-Meng Zhang kai xiong Cheng-Chen Jin Zong-Bo Li Jun-Jie He Yong Mao National Center for International Research on Photoelectric and Energy Materials School of Materials and EnergyMaterials Genome InstituteYunnan UniversityKunming 650091China

The Pt3Hf compound plays a decisive role in strengthening Pt-Hf alloy *** the stacking fault,dislocation dissociation,and twinning mechanisms in Pt3Hf is the first step in understanding its plastic *** this work,the generalized stacking fault energies(GSFE),including the complex stacking fault(CSF),the superlattice intrinsic stacking fault(SISF),and the antiphase boundary(APB) energies,are calculated using firstprinciples *** dislocation dissociation,deformation twinning,and yield behavior of Pt3Hf are discussed based on GSFE after their incorporation into the Peierls-Nabarro *** found that the unstable stacking fault energy(γus) of(111)APB is lower than that of SISF and(010) APB,implying that the energy barrier and critical stress required for(111)APB generation are lower than those required for(010)APB *** result indicates that the a superdislocation will dissociate into two collinear a/2 superpartial *** a/2 dislocation could further dissociate into a a/6 Shockley dislocation and a a/3 superShockley dislocation connected by a SISF,which results in an APB→SISF *** study also discovered that Pt3 Hf exhibits normal yield behavior,although the cross-slip of a a/2 dislocation is not forbidden,and the anomalous yield criterion is ***,it is observed that the energy barrier and critical stress for APB formation increases with increasing pressure and decreases as the temperature is *** the temperature rises above 1400 K,the a/2 dislocation slipping may change from the {111} planes to the {100} planes.

关键词： Platinum alloys Stacking fault energy Dislocation dissociation Twinning First-principles