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66th International Astronautical Congress 2015: Space - The Gateway for Mankind's Future, IAC 2015

作者： Zhang, Shengjun Liu, Jiaqi Liu, Xin China Academy of Launch Vehicle Technology National Key Laboratory on Test Physics and Numerical Mathematics China

ISBN: (纸本)9781510818934

As the development of the activities in space, militarization on space and space debris bring more and more risks and danger to the world. It is a worldwide problem to keep space in a security and safety situation. With years of development in astronautics, more and more space activities actualized in China as well as the cooperation on space items between China and many other countries, both academic groups and government of China now pay more attentions on the activities itself and the space environment for peace use of space and the convenient life in the information days. Many researches have been sponsored by the government in recent three decades. There are two types of research groups, including the academic part (such the professors and their students) and space organizations, concerning on topics such as legal affairs, space debris and other. The study of these groups as well as their cooperation with international groups contributed much to concerning and the decision-making of the government, even leading to the TCBM and PPWT.

关键词： Space debris

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1-bit Coding Metasurface for Wideband RCS Reduction

1-bit Coding Metasurface for Wideband RCS Reduction

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

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

ISBN: (纸本)9781665452366

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. © 2022 IEEE.

关键词： Plate metal

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Theoretical Simulation and Experimental Analysis of Electromagnetic Wave Propagation characteristics in Sub-dense Nonuniform Plasma 4

Theoretical Simulation and Experimental Analysis of Electrom...

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4th International Applied Computational Electromagnetics Society Symposium in China, ACES-China 2021

作者： Wu, Runhui Liu, Jiaqi Chai, Song Meng, Gang Li, Yanan Cui, Yichun Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics Numerical Mathematics Beijing China

In this paper, reflection, absorption and transmission characteristics of 1-50GHz frequency electromagnetic wave by the sub-dense heterogeneous plasma are studied by combining theoretical modeling and simulation with ... 详细信息

ISBN: (纸本)9781733509619

关键词： Computation theory

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An Ultra Wideband FSS Operating at Ka Band 5

An Ultra Wideband FSS Operating at Ka Band

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5th IEEE International Conference on Computational Electromagnetics, ICCEM 2019

作者： Xu, Yinfang Zhang, Shengjun National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

ISBN: (纸本)9781538671115

An Ultra Wideband frequency selective surface (FSS) with forth-order bandpass responses operating at Ka band is proposed in the paper. To improve the performance of the FSS especially in angular stability, the coupling of capacitive surface and inductive surface is employed to realize the miniaturization of the structural unit around 0.26λ. Furthermore, to enhance the passband and to suppress sharply the bandstop edge of the FSS, a multi-layer FSS structure is adopted to form a forth-order filter. In addition, the FSS working at the Ka band frequency with a low-profile broadband and a high rejection stopband is designed. The proposed FSS can provide sharp frequency selectivity and stable frequency responses as functions of angle and polarization of incidence of the EM wave. Principles of operation, detailed design, and simulated results of the fabricated prototypes are presented and discussed in this paper. © 2019 IEEE.

关键词： Frequency selective surfaces

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Frequency hopping signal parameter estimation algorithm based on time-frequency point correlation 10

Frequency hopping signal parameter estimation algorithm base...

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10th IEEE Joint International Information technology and Artificial Intelligence Conference, ITAIC 2022

作者： Jiang, Zhiye Wang, Shangyue Chen, Yang Wang, Peng Gao, Lu Beijing Institute of Space Long March Vehicle National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China

ISBN: (数字)9781665422079

ISBN: (纸本)9781665422079

Aiming at the low accuracy of frequency hopping signal parameter estimation under the influence of complex noise and interference, a frequency-hopping signal parameter estimation algorithm based on time-frequency point correlation is proposed. First, we design the kernel function to obtain the time-frequency distribution of the frequency-hopping signal. Then, we use the correlation of the time-frequency points to establish the target transfer relationship model. Besides, the feature quantity combines density screening is used for hierarchical clustering, and ridge queuing methods filter out the interference ridge label. Finally, we perform parameter estimation on the frequency hopping ridge. The simulation results show that the parameter error estimated by the proposed algorithm continues to decrease with the improvement of the signal-to-noise ratio. In the case of -6dB, the error of each parameter is as low as about 0.1. This algorithm can completely extract the frequency hopping ridge under the condition of a low signal-to-noise ratio, achieve an excellent parameter estimation effect, and provide a reference for communication signal parameter estimation. © 2022 IEEE.

关键词： Frequency hopping

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The Study on Porous Media Phase Change Coupling Heat transfer model in Enclosed Metal Cavity

The Study on Porous Media Phase Change Coupling Heat transfe...

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The 2nd International Conference on Materials science and Engineering technology (MSET 2015)

作者： WU Run-hui LIU Jia-qi LIU Xin REN Ai-min ZHANG Sheng-jun MENG Gang National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical

This thesis is aimed to the external instantaneous high energy heat source,according to enclosed metal cavity,porous medium in the cavity,porous media can by phase change heat transfer characteristic of variegated medium coupling state target's special requirements in the field of aerospace,it is innovatively to put forward a kind of applicable to simulate sealed coupling target,under the condition of instant high energy heat source excitation,By heat source-metal cavityporous medium—porous medium's phase-changeable phase change process heat-transfer characteristic numerical calculation model-creation approach,in use of the metal cavity,in the porous medium incompressible flow phase transition of working medium's heat energy conservation,momentum conservation and mass conservation principle,it is to establish analysis model of coupled heat transfer characteristics of multiple parts,in order to acquire the full target area of airtight coupling state targets,temperature field,pressure field,velocity field and phase change of phase transition of working medium characteristics change with time and space change numerical value to analog *** study results points out:when the incentive heat source keep constant,the change rule of full target area temperature,pressure flow rate and phase change characteristic parameters is in conformity with theory of heat transfer *** heat transfer model can be popularized and applied to the optimization design of incentive heat source,and comprehensive performance optimization of enclosed coupling state objects.

关键词： Enclosed metal cavity,Porous foam materials,Phase transition working medium,Heat transfer model,numerical modeling

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An Improved Adaptive Pulse Compression Algorithm Based on Linear Frequency Modulation Signal

An Improved Adaptive Pulse Compression Algorithm Based on Li...

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2019 IEEE International Conference on Signal, Information and Data Processing, ICSIDP 2019

作者： Bai, Jinliang Qin, Peng Li, Hu Zhang, Ran Zhang, Xinyu National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing Institute of Space Long March Vehicle Beijing China

ISBN: (纸本)9781728123455

In this paper, the radar signal is optimized based on the pulse compression repair (PCR) algorithm, which mainly reduces the computational amount to makes it more advantageous to achieve. The main idea is to implement PCR in a parallel way. The method of implementing parallelism is well known, that is, the signal is segmented, and different segmentation methods can be adopted according to different signal models. In this paper, the chirp signal is mainly processed by decimation and segmentation, and some intrinsic benefits of the performance and computational balance of the proposed method are discussed. © 2019 IEEE.

关键词： Frequency modulation

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Adaptive feed-forward control for seeker based on the disturbance observer 4

Adaptive feed-forward control for seeker based on the distur...

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4th IEEE Advanced Information technology, Electronic and Automation Control Conference, IAEAC 2019

作者： Liu, Xin Niu, Zhenhong Shu, Yi Xue, Lian Zhu, Mingchao National Key Laboratory of Science and Technology on Test Physics Numerical Mathematics China Chinese Academy of Sciences Changchun Institute of Optics Mechanics and Physics China

ISBN: (纸本)9781728119076

In order to improve the tracking and stabilization performance, a control method combining disturbance observer and adaptive feed-forward control using parameterization is proposed for seeker stabilized platforms. The system identification algorithm is used to identify dynamic model of the true plant. Then the discrete-time disturbance observer is designed. The feedback loop controller is designed using pole-placement techniques. The recursive least square (RLS) adaptive filter is used to build the inverse model of the feedback control loop and in this way, the feed-forward control is constructed. The adaptive filter and the feedback loop constitute a control scheme with two degrees-of-freedom (DOF). Tracking experiments conducted on velocity command inputs verify the validity of the adaptive feed-forward controller. Experimental results show that this method responses quickly to commands. For a sinusoidal signal at the frequency of 30Hz, the adaptive feed-forward controller can obtain an amplitude response without attenuation and the phase lag is reduced to 11° in contrast with the feedback control whose phase lag is 60°. This method significantly improves the transient performance and is superior to the feedback control alone. © 2019 IEEE.

关键词： Adaptive filters

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A High Temperature Resistant Broadband Metamaterial Absorber

A High Temperature Resistant Broadband Metamaterial Absorber

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2023 International Applied Computational Electromagnetics Society Symposium, ACES-China 2023

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

ISBN: (纸本)9781733509657

Based on high temperature resistant silicon dioxide(SiO2) 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 SiO2 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. © 2023 Applied Computational Electromagnetics Society (ACES).

关键词： Silica

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Multiple model PHD filter for tracking sharply maneuvering targets using recursive RANSAC based adaptive birth estimation

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Journal of Systems Engineering and Electronics 2024年第3期35卷 780-792页

作者： DING Changwen ZHOU Di ZOU Xinguang DU Runle LIU Jiaqi School of Astronautics Harbin Institute of TechnologyHarbin 150001China School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150001China National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing 100076China

An algorithm to track multiple sharply maneuvering targets without prior knowledge about new target birth is proposed. These targets are capable of achieving sharp maneuvers within a short period of time, such as drones and agile *** probability hypothesis density (PHD) filter, which propagates only the first-order statistical moment of the full target posterior, has been shown to be a computationally efficient solution to multitarget tracking problems. However, the standard PHD filter operates on the single dynamic model and requires prior information about target birth distribution, which leads to many limitations in terms of practical applications. In this paper,we introduce a nonzero mean, white noise turn rate dynamic model and generalize jump Markov systems to multitarget case to accommodate sharply maneuvering dynamics. Moreover, to adaptively estimate newborn targets’information, a measurement-driven method based on the recursive random sampling consensus (RANSAC) algorithm is proposed. Simulation results demonstrate that the proposed method achieves significant improvement in tracking multiple sharply maneuvering targets with adaptive birth estimation.

关键词： multitarget tracking probability hypothesis density(PHD)filter sharply maneuvering targets multiple model adaptive birth intensity estimation

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