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2023 International Conference on Image, Signal Processing, and Pattern Recognition, ISPP 2023

作者： Huang, Dingkun Yan, Xiaopeng Lv, Minghui Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical Engineering Beijing Institute of Technology Beijing100081 China

ISBN: (纸本)9781510666351

To improve the real-time performance of radiation source signal time-frequency analysis, a fast radiation source signal time-frequency feature extraction method based on low-order cyclic statistics and Choi-Williams transform is proposed. First, the low-order cyclic statistics of the radiation source signal are calculated. Second, the IFFT is used to recover the cyclic domain signal, and the number of sampling points of the radiation source signal is adaptively controlled by the cyclic mean and IFFT point number. Finally, the recovered signal is used for CWD time-frequency analysis. In order to highlight the time-frequency image features, the geometric features of the signal modulation type are extracted using binary image transformation. Simulation analysis shows that the proposed time-frequency preprocessing method can significantly reduce the computational complexity while maintaining the accuracy of time-frequency features and improving real-time performance, providing effective support for subsequent sorting and recognition and parameter estimation work. © 2023 SPIE.

关键词： Binary images

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A range-angle estimation algorithm for array FMCW radar based on spatial and temporal sparse extending

A range-angle estimation algorithm for array FMCW radar base...

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2023 International Conference on Image, Signal Processing, and Pattern Recognition, ISPP 2023

作者： Wang, Xinwei Yan, Xiaopeng Han, Yanwen Huang, Dingkun Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical Engineering Beijing Institute of Technology Beijing100081 China

ISBN: (纸本)9781510666351

Array frequency modulated continuous wave (FMCW) radar is widely used across various platforms to estimate the range and angle of targets using large bandwidth and array angle measurement technology. However, limited platform space and antenna aperture can make obtaining high-precision angle estimations challenging. To address this, a range-angle estimation algorithm based on spatial and temporal sparse extending is proposed. The algorithm extends the array using a nested array in the spatial domain and a sparse virtual array sampled at different locations through platform movement in the temporal domain. The resulting spatial-temporal extended array is equivalent to a large aperture virtual uniform linear array, improving the angle resolution through difference and spatial smoothing processing. By making full use of spatial and temporal information, this method achieves high-precision angle estimation with fewer array elements. © 2023 SPIE.

关键词： Frequency modulation

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Research on Identification of Fire Signal of a Certain Type of Rocket 4

Research on Identification of Fire Signal of a Certain Type ...

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4th International Conference on Defence technology, ICDT 2024

作者： Guo, Pengda Wang, Yabin Luan, Donglin Yang, Shanglin School of Mechatronical Engineering Beijing Institute of Technology Beijing China Science and Technology on Electromechanical Dynamic Control Laboratory China

To assess the contradiction between ballistic safety and ignition reliability in traditional rocket projectile inertial initiation mechanisms, this study focuses on the recognition of graze bursting ignition signals for a specific type of rocket projectile. By utilizing a finite element numerical simulation method to model the small-angle impact of the rocket projectile on a target, the overload information can be extracted from the ignition mechanism. The accuracy of the simulation model can be validated by comparing it with data obtained from live ammunition tests. Through a series of simulations, the ignition threshold can be determined by the maximum velocity change vector within different time windows of the ignition mechanism. And the integration algorithm is used to accumulate the overload value of the ignition mechanism in the time window to judge whether the velocity change threshold is reached, and then judge whether to output the ignition signal. The algorithm verification shows that the algorithm can effectively identify the ignition signal under the set ignition threshold. This method provides a basis for recognizing the graze bursting ignition signal. © 2024 Institute of Physics Publishing. All rights reserved.

关键词： Projectiles

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technology of shipboard two-way microwave time synchronization

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Journal of Beijing Institute of technology 2014年第4期23卷 511-518页

作者：付永杰李东光刘旭东 Science and Technology on Electormechanical Dynamic Control Laboratory Beijing Institute of Technology Unit 92493 of PLA Huludao

For the high precision time synchronization demand of ships, advantages and disadvantages of the present time transfer methods are analyzed, the two-way microwave time transfer （TWMTT） method is adopted to resolve the time synchronization problem in the Naval Ship Formation. After expounding the principle and system composition of TWMTT method, the various factors influencing the synchronous precision are analyzed, such as time-interval measurement error, TWMTT equipment delay error, signal propagation error in air, and signal delay error caused by shipping. To improve the time synchronization precision, all the error sources above are deduced with mathematical measures to definite the critical one, and the signal processing measures such as Pseudo code spread spectrum time comparison signal generation technology, FFT fast acquisition technology and precise tracking technology are used into the modem which is the core equipment of the TWMTT. And, calibration method of TWMTT equipment delay are developed. Through theoretical a- nalysis and simulation verification, the precision of shipboard two-way microwave time synchroniza- tion can reach 1 ns.

关键词： two-way microwave time transfer（TWMTT） time synchronization time delay error analysis

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Microfluidic inertial switch with delay response characteristics 2

Microfluidic inertial switch with delay response characteris...

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2nd Spring International Conference on Defence technology, ICDT 2020

作者： Nie, Weirong Liu, Guowei Zhang, Runduo School of Mechanical Engineering Nanjing University of Science and Technology Nanjing China Science and Technology on Electromechanical Dynamic Control Laboratory Xi'an China

This paper proposes an innovation microfluidic inertial switch structure with precise time delay response characteristic, which can be used in the fuze safety and arming system. The switch works on the principle of fluidic inertial force and capillary valve, which makes it sensitive to the unidirection acceleration load and has the ability to recognize the acceleration amplitude. The microfluidic inertial switch has a structure of a J-shaped reservoir, capillary valves, a serpentine delay microchannel and a U-shaped latching microchannel. The acceleration threshold is analyzed theoretically considering the surface tension coefficient of the gas-liquid interface. The delay response time of the switch is studied by finite element simulation based on the Gambit 2.4 and Fluent 6.3 software. The prototype is fabricated by wet etching technology and magnetron sputtering metal technology. Many tests have been done to verify the functions of the switch. The experimental results are matched well to the results of calculation and simulation. When the capillary valve throat widths are 80μm, 120μm, 160μm, the thresholds of the switch are 75.1g, 46.6g, 36.5g. When the switch is loaded with a 75g acceleration load, the delay response is 146.7ms. Finite element simulation and experimental results show that the switch can effectively identify the acceleration threshold, and can achieve a precise delay response under a certain load. © Published under licence by IOP Publishing Ltd.

关键词： Microchannels

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Segmentation Clustering Algorithm for Point Cloud Processing of Targets on the Ground 3

Segmentation Clustering Algorithm for Point Cloud Processing...

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3rd International Conference on Defence technology, ICDT 2022

作者： Huang, Jinbo Zheng, Zhen Zhang, Yifei Zhou, Yu School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China Science and Technology on Electromechanical Dynamic Control Laboratory China

After the ground extraction algorithm, there are multiple objects, including the target in the non-ground point cloud. To effectively extract the features of individual objects and overcome the dependence of the traditional algorithm based on the normal vector and curvature of the region growing point cloud segmentation method on the initial point, the normal vector angle in the neighborhood, and the curvature threshold selection. In this paper, we propose a fast clustering segmentation method for region-growing point clouds based on neighborhood density. The test results show that the point cloud segmentation algorithm proposed in this paper has better performance than the traditional Euclidean clustering point cloud segmentation algorithm and region growing point cloud segmentation algorithm in terms of timeliness and correct segmentation rate. This new segmentation clustering algorithm can quickly implement automatic point cloud clustering segmentation of ground objects. © Published under licence by IOP Publishing Ltd.

关键词： Clustering algorithms

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Research on the characteristics of wireless power transfer in non-ferromagnetic metal pipe

Research on the characteristics of wireless power transfer i...

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2020 International Symposium on Electronic Information technology and Communication Engineering, ISEITCE 2020

作者： Li, Changsheng Liu, Yong Hu, Defu Sun, Wei Science and Technology on Electromechanical Dynamic Control Laboratory China Ministerial Key Laboratory of Zndy Nanjing University of Science and Technology Nanjing Jiangsu210094 China

With the development of various electronics, the way of transmitting energy by wire has brought increasingly negative effects on the operability and convenience of products. As wireless power transfer (WPT) technology requires no transmission lines, it has received increasingly wide attention. Most of the previous research on the technology of magnetic resonant coupling WPT mainly focused on the transmission of energy in the air. This paper establishes the wireless power transfer system model under non-ferromagnetic metallic environment and studies the effect of non-ferromagnetic metallic environment on coil self-inductance L, mutual inductance M and coil resistance R of WPT system. On this basis, the study on the relationship between coil diameter and mutual inductance is carried out for aluminium pipe, and the relationship between coil diameter and diameter of metal pipe at the maximum mutual inductance is fitted. Besides, experimental verification is conducted for the change of mutual inductance between the coils of WPT system in the aluminium pipe, presenting that the actual measurement results of mutual inductance in the aluminium pipe are consistent with the theory. © Published under licence by IOP Publishing Ltd.

关键词： Ferromagnetic materials

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Point Cloud Target Registration Algorithm Based on Local Feature Description 3

Point Cloud Target Registration Algorithm Based on Local Fea...

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3rd International Conference on Defence technology, ICDT 2022

作者： Wang, Chengjun Zha, Binting School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China Science and Technology on Electromechanical Dynamic Control Laboratory China

Point cloud data has received extensive attention in the field of target recognition and target tracking due to its rich target information, and point cloud registration is one of the basic tasks in point cloud applications. Aiming at the problem that the feature descriptor in the traditional registration algorithm is complicated to calculate and cannot sufficiently describe the features of the point cloud, this paper proposes a local feature descriptor that integrates the local normal vector angle features, projection distance features, and distribution density features of the point cloud. The feature similarity is introduced to determine the corresponding point pairs between the template point cloud and the target point cloud, and the point cloud registration task is completed based on local feature matching. Experiments show that the feature descriptor in this paper is simple to calculate and can sufficiently describe the local features of the point cloud, a good correspondence between points can be established based on the feature descriptor, and the algorithm has good robustness. The registration algorithm proposed in this paper can provide a reference for the fields of target recognition and target pose estimation, etc. © Published under licence by IOP Publishing Ltd.

关键词： Target tracking

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Research on the Characteristics of Wireless Power Transfer in Ferromagnetic Metal Pipe 4

Research on the Characteristics of Wireless Power Transfer i...

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2020 4th International Conference on Electrical, Mechanical and Computer Engineering, ICEMCE 2020

作者： Li, Changsheng Sun, Wei Hu, Defu Liu, Yong Science and Technology on Electromechanical Dynamic Control Laboratory China Ministerial Key Laboratory of Zndy Nanjing University of Science and Technology Nanjing Jiangsu210094 China

With the development of society, radio energy transmission technology has been paid more and more attention. However, in the actual application environment, the surrounding metal environment has a significant impact on the radio energy transmission performance. Based on the technology of MRR radio energy transmission, this paper establishes a two coil radio energy transmission model, and analyzes the influence of metal environment on the coil self inductance L, mutual inductance m and coil resistance R of the radio energy transmission system by finite element simulation. On this basis, aiming at the ferromagnetic metal environment, the steel pipe is selected as the research object to study the relationship between coil diameter and mutual inductance in the metal pipe, and the relationship between coil diameter and metal pipe diameter when the maximum mutual inductance is obtained through fitting analysis. At the same time, through the experiment, the mutual inductance between the coils of the wireless energy system in the steel tube is verified, and the experimental results are very consistent with the theory. © Published under licence by IOP Publishing Ltd.

关键词： Ferromagnetic materials

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Fuel-optimal trajectory design using solar electric propulsion under power constraints and performance degradation

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science China(Physics,Mechanics & Astronomy) 2014年第6期57卷 1090-1097页

作者： ZHANG Peng LI JunFeng GONG ShengPing School of Aerospace Tsinghua University Science and Technology on Aerospace Flight Dynamic Laboratory Beijing Aerospace Control Center

The fuel-optimal transfer trajectories using solar electric propulsion are designed considering the power constraints and solar array performance *** different performance degradation models including linear,positive and negative exponential degradations are used in the analysis of three typical rendezvous missions including Apophis,Venus and Ceres,*** optimal control problem is formulated using the calculus of variations and Pontryagin’s maximum principle,which leads to a bang-bang control that is solved by indirect method combined with a homotopic *** demonstrating the effects of the power constraints and solar array performance degradation on the power budget and fuel consumption,the time histories of the power profile and the fuel consumptions are compared for the three *** study indicates that it is necessary to consider the power constraints and solar array performance degradation for the SEP-based low-thrust trajectory design,espacially for long-duration outbound flights.

关键词： fuel-optimal trajectory solar electric propulsion power constraints performance degradation

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