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IEEE Radar Conference

作者： Runle Du Jiaqi Liu Yonghai Wang Zhifeng Li Chunyue Gao National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Aero-Top Hi-Tech Corporation Ltd.

ISBN: (纸本)9781467357920

When multiple flying vehicles with bearing-only tracking collaborate in locating a target, observation data fusion is required to compensate the drift of navigation system, the noise from observation system, and the unknown maneuvering of target object. Kalman Filtering of nonlinear observation data needs a huge amount of computation, and will cause trouble to onboard embedded computing systems. Least Squared Error (LSE) can process nonlinear measurements at high speed, but the observation noise may be amplified due to the intrinsic deficiency. In this paper, a Fast Data Fusion algorithm is proposed. It combined these two methodologies. LSE is used as the preprocessing stage to build a coarse estimation and Kalman Filtering is used to further eliminate noises from preprocessed estimations. Simulation results show that, proposed method uses no more than 3% of computation time of Kalman Filtering and achieved similar or even better target locating precision.

关键词： Formation Flying Bearing-only Tracking Passive Target Location Fast Data Fusion Kalman Filtering

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Parallel pipeline algorithm of real time star map preprocessing

Parallel pipeline algorithm of real time star map preprocess...

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Chinese Society for Optical Engineering Conferences, CSOE 2016

作者： Wang, Hai-Yong Qin, Tian-Mu Liu, Jia-Qi Li, Zhi-Feng Li, Jian-Hua School of Aeronautics and Astronautics Beihang University Beijing100083 China Beijing Institute of Space Long March Vehicle Beijing100076 China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematical Beijing100076 China

ISBN: (纸本)9781510610118

To improve the preprocessing speed of star map and reduce the resource consumption of embedded system of star tracker, a parallel pipeline real-time preprocessing algorithm is presented. The two characteristics, the mean and the noise standard deviation of the background gray of a star map, are firstly obtained dynamically by the means that the intervene of the star image itself to the background is removed in advance. The criterion on whether or not the following noise filtering is needed is established, then the extraction threshold value is assigned according to the level of background noise, so that the centroiding accuracy is guaranteed. In the processing algorithm, as low as two lines of pixel data are buffered, and only 100 shift registers are used to record the connected domain label, by which the problems of resources wasting and connected domain overflow are solved. The simulating results show that the necessary data of the selected bright stars could be immediately accessed in a delay time as short as 10us after the pipeline processing of a 496×496 star map in 50Mb/s is finished, and the needed memory and registers resource total less than 80kb. To verify the accuracy performance of the algorithm proposed, different levels of background noise are added to the processed ideal star map, and the statistic centroiding error is smaller than 1/23 pixel under the condition that the signal to noise ratio is greater than 1. The parallel pipeline algorithm of real time star map preprocessing helps to increase the data output speed and the anti-dynamic performance of star tracker. © 2017 SPIE.

关键词： Pipelines

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A High Temperature Resistant Broadband Metamaterial Absorber

A High Temperature Resistant Broadband Metamaterial Absorber

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yinfang Xu Jiaqi Liu Lu Gao Xia Ai National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

Based on high temperature resistant silicon dioxide(SiO 2 ) and silicon carbide(SiC) materials, a high temperature resistant broadband meta material absorber was designed in this paper. The absorber consists of two layers of SiC pattern, three layers of $\text{SiO}_{2}$ transmission medium, and a bottom layer of low resistance SiC thin film reflection layer. The simulation results show that the absorption rate of the absorber exceeds 90% in the frequency range of 3.46-18.37GHz, and the relative absorption bandwidth is 136.6%. The absorber device also has the characteristics of low process implementation difficulty, polarization insensitivity, and wide-angle absorption. Therefore, it has potential application value in fields such as radar imaging, stealth, and communication technology.

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1-bit Coding Metasurface for Wideband RCS Reduction

1-bit Coding Metasurface for Wideband RCS Reduction

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International Applied Computational Electromagnetics Society Symposium (ACES)

作者： Yinfang Xu Jiaqi Liu Lu Gao Xia Ai Zhongjie Zhang Huan Liang National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

This paper achieve efficient RCS reduction over a wide frequency range by exploiting the reflection properties of the coding metasurface. The metasurface consists of “0” cells and “1” cells, and the reflection phase difference is close to 180° over a wide frequency range. By designing the spatial random coding arrangement of “0” units and “1” units, the electromagnetic waves incident on the metasurface form diffuse reflection, so as to achieve the purpose of broadband RCS reduction. The simulation results show that when the incident wave is irradiated vertically, the metasurface can basically achieve a RCS reduction of more than 10dB in a wide frequency band of 10-20.5GHz compared to a metal plate of the same size. In the case of oblique incidence, the RCS reduction still has a good effect, which is basically the same as the curve at normal incidence, and has the characteristics of wide-angle incidence RCS reduction. The reduced bandwidth of the broadband RCS of the coding metasurface is basically consistent with the 10 dB polarization bandwidth of the cell structure. The design of the metasurface is simple and efficient, so it has great application potential in stealth new technologies and new materials.

关键词： Electric potential Simulation Electromagnetic scattering Metals Metasurfaces Computational electromagnetics Reflection

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Research on the stability of multi-gap extended cavity for W band Sheet beam EIK

Research on the stability of multi-gap extended cavity for W...

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International Conference on Vacuum Electronics

作者： Shuyuan Chen Jiaqi Liu Zhiye Jiang Lu Gao Jingliang Bai Yong Wang National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing P. R. China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing 100076 China Key Laboratory of High Power Microwave Sources and Technologies Chinese Academy of Sciences Beijing P. R. China

ISBN: (纸本)9781479971114

A sheet-beam Extended Interaction Klystron (SBEIK) is an attractive MMW amplifier because of its high gain per unit length and compact configuration.[1-3] However, with a large width-high ratio sheet beam, it is easier to become instable in long transmission distance. In this paper, the stability of multi-gap extended cavity for W band Sheet beam EIK has been studied. The method for judging oscillation has been proposed. The electronic conductance of multi-gap extended cavity has been calculated. The result has been demonstrated by 3D-PIC software.

关键词： Cavity resonators Software Radio frequency Oscillators

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Intelligent Assignment Strategy for Multi-Target Adversarial Interception

Intelligent Assignment Strategy for Multi-Target Adversarial...

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2022 Chinese Automation Congress, CAC 2022

作者： Yu, Yang Fang, Yizhong Wu, Han Han, Tuo Hu, Qinglei Beihang University School of Automation Science and Electrical Engineering Beijing100191 China Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing100076 China Beihang University School of Aeronautic Science and Engineering Beijing100191 China Hangzhou310023 China

ISBN: (纸本)9781665465335

The multi-missile confront multi-target is a classic target allocation issue in the combat scenario of multiple missiles intercepting multiple maneuvering targets. Traditional algorithms lack environmental assessment model, train quality, and indicator function in the adversarial environment. To this end, this paper aims to propose an intelligent assignment strategy which contains indicator function and evaluation model. Then, an indicator function and an evaluation model considering the miss distance, threat situation, and the number of specified interception targets are introduced into the reinforcement learning algorithm. The local and global reward functions are introduced to improve the training convergence and efficiency in the multi-missile multi-target confrontation scenario. Finally, simulation results are designed to check on advantage of intelligent allocation strategy. © 2022 IEEE.

关键词： Reinforcement learning

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Physical Layer Security of Cooperative Network with Machine Learning-based Relay Selection

Physical Layer Security of Cooperative Network with Machine ...

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IEEE International Symposium on Electromagnetic Compatibility (EMC-Beijing)

作者： Fang Liu Yajuan Wang Hu Li Beijing University of Posts and Telecommunications Beijing China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

ISBN: (数字)9781728144160

ISBN: (纸本)9781728144177

We explore the potential of machine learning for relay selection in a cooperative multi-relay wiretap network with decode-and-forward (DF) protocol, aiming to enhance the physical layer security. Such network is divided into two scenarios according to whether the channel state information (CSI) of wiretap links is available or not for source, when it is assumed that the CSI of the main links has been known at the source. In addition, two machine learning-based schemes, namely, the convolutional neural network(CNN)-based multi-classifier and the support vector machine(SVM)-based multi-classifier, are proposed to characterize the conventional optimization problem of cooperative relay selection as a multi-classification problem in two scenarios mentioned above. In our study, we provide more insight into the spatial correlation of CSI and make the first attempt to introduce the CNN for relay selection in a cooperative multi-relay wiretap network. Finally, the simulation results indicate that two machine learning-based with relatively low selection complexity and less feedback amount achieve substantially the same secrecy performance as the conventional selection scheme.

关键词： Relays Training Machine learning Support vector machines Physical layer security Neurons Correlation

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Universality of the Dynamic Characteristic Relationship of Electron Correlation in the Two-Photon Double Ionization Process of a Helium-Like System

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Chinese physics Letters 2020年第11期37卷 27-32页

作者： Fei Li Yu-Jun Yang Jing Chen Xiao-Jun Liu Zhi-Yi Wei Bing-Bing Wang Laboratory of Optical Physics Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesBeijing 100190China Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China Institute of Applied Physics and Computational Mathematics Beijing 100088China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100084China State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsInnovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China

Universality of the dynamic characteristic relationship between the characteristic time tc and the two-electron Coulomb interaction energy V12 of the ground state in the two-photon double ionization process is investigated via changing the parameters of the two-electron atomic system and the corresponding laser *** numerical results show that the product tcV12 keeps constant around 4.1 in the cases of changing the nucleus charge,the electron charge,the electron mass,and changing simultaneously the nucleus charge and the electron *** results demonstrate that the dynamic characteristic relationship in the two-photon double ionization process is *** work sheds more light on the dynamic characteristic relationship in ultrafast processes and may find its application in measurements of attosecond pulses.

关键词： conditions. charge characteristic

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Dual-Frequency Vortex Beam Generation Using Coding Metasurface

Dual-Frequency Vortex Beam Generation Using Coding Metasurfa...

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2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Li, Junfeng Kong, Xianglin Wang, Fengjun Miao, Zhuowei Wang, Xiaoyi Shen, Xiaopeng Zhang, Shengjun Zhao, Lei China University of Mining and Technology School of Information and Control Engineering Xuzhou China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical Beijing China Polytechnique Montreal Department of Electrical Engineering MontrealQC Canada China University of Mining and Technology School of Materials Science and Physics Xuzhou China

ISBN: (纸本)9781665452366

This paper presents a dual-frequency coding metasurface (CM) for vortex beam generation. The metasurface unit cell is realized with two symmetric metal layers separated by a dielectric substrate. Each metal layer consists of an outer square ring, a middle square ring, and an inner rhombus patch. Two out-of-phase transmitting states in two bands are achieved by rotating the inner rhombus patch by 90 °. Two 1 = + 2 vortex beams are then realized in two different bands by properly distributing the two states on the metasurface aperture. A metasurface with 30 × 30 elements is designed, simulated, and experimentally demonstrated. The experimental results agree well with the simulating ones, showing that the metasurface achieves a high transforming efficiency in both Ku (13.6-14.8GHz) band and Ka (26.7-27.7 GHz) band. © 2022 IEEE.

关键词： Kurchatovium

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Perturbation Estimated Incremental Guidance for Exo-Atmospheric Interception

Perturbation Estimated Incremental Guidance for Exo-Atmosphe...

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2022 Chinese Automation Congress, CAC 2022

作者： Lu, Yuting Liu, Peng Han, Tuo Hu, Qinglei Beihang University School of Automation Science and Electrical Engineering Beijing100191 China Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing100076 China Beihang University School of Aeronautic Science and Engineering Beijing100191 China Hangzhou310023 China

ISBN: (纸本)9781665465335

In order to meet the requirement of accurate intercept against the increased target maneuverability and external disturbance, a second-order inertial delay based incremental guidance law (IDIASMG) is proposed for an exo-atmospheric interceptor. Specifically, a three-dimensional guidance model is transformed into an incremental version. As a guidance design benchmark, a conventional sliding mode guidance law (SMG) is presented, and a sliding mode incremental guidance law (ISMG) is designed with gain adaptation. Moreover, a second-order inertial delay filter is utilized to estimate and compensate guidance perturbation including the target maneuver, system uncertainty, and external disturbance. Theoretical analysis shows that the incremental guidance requires smaller gains to ensure smaller system residual than the conventional SMG. Extensive numerical simulations validate the effectiveness and robustness of IDIASMG. © 2022 IEEE.

关键词： Uncertainty analysis

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