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Improved spectrum reconstruction technique based on chirp rate modulation in stepped-frequency SAR

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Science China(Information Sciences) 2015年第10期58卷 148-158页

作者： GAO WenBin DING ZeGang ZHU DongLin ZENG Tao LONG Teng radar Research Laboratory School of Information and Electronics

To improve the efficiencies of the traditional spectrum reconstruction techniques, an improved spectrum reconstruction technique(ISRT) based on chirp rate modulation(CRM) is proposed. With the help of a CRM operation, a reconstructed wideband signal with a narrow pulse width can be obtained. Compared with the traditional time domain spectrum reconstruction technique(TSRT), ISRT is less time-consuming since much less samples are needed. Compared with the traditional frequency domain spectrum reconstruction technique(FSRT), the reconstructed signal is a chirp signal, which has no limitation on the subsequent imaging *** is more, processing steps of ISRT are optimized, and the computational burden is less than that of TSRT and FSRT. Both simulation results and real data processing have verified the validity of ISRT.

关键词： chirp rate modulation(CRM) spectral efficiency improved spectrum reconstruction technique(ISRT) spectrum reconstruction stepped-

GraphSTGAN:Situation understanding network of slow-fast high maneuvering targets for maritime monitor services of IoT data

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Digital Communications and Networks 2024年第3期10卷 620-630页

作者： Guanlin Wu Haipeng Wang Yu Liu You He Shenzhen International Graduate school Tsinghua UniversityShenzhen518071China Institute of Space Science and Applied Technology Harbin Institute of TechnologyShenzhen518055China Department of Electronic Engineering Tsinghua UniversityBeijing100084China

With the rapid growth of the maritime Internet of Things(IoT)devices for Maritime Monitor Services(MMS),maritime traffic controllers could not handle a massive amount of data in *** unmanned MMS,one of the key technologies is situation ***,the presence of slow-fast high maneuvering targets and track breakages due to radar blind zones make modeling the dynamics of marine multi-agents difficult,and pose significant challenges to maritime situation *** order to comprehend the situation accurately and thus offer unmanned MMS,it is crucial to model the complex dynamics of multi-agents using IoT big ***,previous methods typically rely on complex assumptions,are plagued by unstructured data,and disregard the interactions between multiple agents and the spatial-temporal correlations.A deep learning model,Graph Spatial-Temporal Generative Adversarial Network(GraphSTGAN),is proposed in this paper,which uses graph neural network to model unstructured data and uses STGAN to learn the spatial-temporal dependencies and *** experiments show the effectiveness and robustness of the proposed method.

关键词： Internet of things Multi-agents Graph neural network Maritime monitoring services

Electromagnetic scattering and imaging simulation of extremely large-scale sea-ship scene based on GPU parallel technology

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Journal of Electronic Science and Technology 2024年第2期22卷 16-23页

作者： Cheng-Wei Zhang Zhi-Qin Zhao Wei Yang Li-Lai Zhou Hai-Yu Zhu Southwest China Institute of Electronic Technology Chengdu610036China school of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China Tencent Company Shenzhen518054China

Aiming to solve the bottleneck problem of electromagnetic scattering simulation in the scenes of extremely large-scale seas and ships,a high-frequency method by using graphics processing unit(GPU)parallel acceleration technique is *** the implementation of different electromagnetic methods of physical optics(PO),shooting and bouncing ray(SBR),and physical theory of diffraction(PTD),a parallel computing scheme based on the CPU-GPU parallel computing scheme is realized to balance computing ***,a multi-GPU framework is further proposed to solve the computational difficulty caused by the massive number of ray tubes in the ray tracing *** using the established simulation platform,signals of ships at different seas are simulated and their images are achieved as *** is shown that the higher sea states degrade the averaged peak signal-to-noise ratio(PSNR)of radar image.

关键词： Multi graphics processing unit radar imaging Sea-ship Shooting and bouncing rays

Fusion of Ground-Based and Spaceborne radar Precipitation Based on Spatial Domain Regularization

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Journal of Meteorological Research 2024年第2期38卷 285-302页

作者： Anfan HUANG Leilei KOU Yanzhi LIANG Ying MAO Haiyang GAO Zhigang CHU school of Atmospheric Physics Nanjing University of Information Science&TechnologyNanjing 210044 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044

High-quality and accurate precipitation estimations can be obtained by integrating precipitation information measures using ground-based and spaceborne radars in the same target *** the true precipitation state is a typical inverse problem for a given set of noisy radar precipitation *** regularization method can appropriately constrain the inverse problem to obtain a unique and stable *** different types of precipitation with different prior distributions,the L_(1) and L_(2) norms were more effective in constraining stratiform and convective precipitation,*** a combination of L_(1) and L_(2) norms,the Huber norm is more suitable for mixed precipitation *** study uses different regularization norms to combine precipitation data from the C-band dual-polarization ground radar(CDP)and dual-frequency precipitation radar(DPR)on the Global Precipitation Measurement(GPM)mission core *** to single-source radar data,the fused figures contain more information and present a comprehensive precipitation structure encompassing the reflectivity and precipitation *** 27 precipitation cases,the fusion results utilizing the Huber norm achieved a structural similarity index measure(SSIM)and a peak signal-to-noise ratio(PSNR)of 0.8378 and 30.9322,respectively,compared with the CDP *** fusion results showed that the Huber norm effectively amalgamate the features of convective and stratiform precipitation,with a reduction in the mean absolute error(MAE;16.1%and 22.6%,respectively)and root-mean-square error(RMSE;11.7%and 13.6%,respectively)compared to the 1-norm and ***,in contrast to the fusion results of scale recursive estimation(SRE),the Huber norm exhibits superior capability in capturing the localized precipitation intensity and reconstructing the detailed features of precipitation.

关键词： dual-frequency precipitation radar(DPR) dual-polarization radar data fusion regularization Huber norm

LFM radar Source Passive Localization Algorithm Based on Range Migration

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Journal of Beijing Institute of Technology 2024年第2期33卷 130-140页

作者： Dandan Li Deyi Wang Hao Huan Beijing Key Laboratory of Fractional Signals and Systems School of Information and ElectronicsBeijing Institute of TechnologyBeijing 100081China Beijing Aerospace Automatic Control Institute Beijing 100854China

Traditional single-satellite passive localization algorithms are influenced by frequency and angle measurement accuracies,resulting in error estimation of emitter position on the order of ***,a single-satellite localization algorithm based on passive synthetic aper-ture(PSA)was introduced,enabling high-precision ***,its estimation of azimuth and range distance is considerably affected by the residual frequency offset(RFO)of uncoopera-tive system ***,it requires data containing a satellite flying over the radia-tion source for RFO *** estimating the RFO,an accurate estimation of azimuth and range distance can be carried out,which is difficult to achieve in practical *** LFM radar source passive localization algorithm based on range migration is proposed to address the dif-ficulty in estimating frequency *** algorithm first provides a rough estimate of the pulse repetition time(PRT).It processes intercepted signals through range compression,range interpola-tion,and polynomial fitting to obtain range migration ***,it uses the changing information of range migration and an accurate PRT to formulate a system of nonlinear equations,obtaining the emitter position and a more accurate PRT through a two-step localization *** offset only induces a fixed offset in range migration,which does not affect the changing *** algorithm can also achieve high-precision localization in squint ***,the effectiveness of this algorithm is verified through simulations.

关键词： passive localization range migration residual frequency offset

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Visual-simulation region proposal and generative adversarial network based ground military target recognition

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Defence Technology（防务技术） 2022年第11期18卷 2083-2096页

作者： Fan-jie Meng Yong-qiang Li Fa-ming Shao Gai-hong Yuan Ju-ying Dai Department of Space Test and Launch Noncommissioned Officer SchoolSpace Engineering UniversityBeijing102299China Department of Mechanical Engineering College of Field EngineeringArmy Engineering University of PLANanjing210007China

Ground military target recognition plays a crucial role in unmanned equipment and grasping the battlefield dynamics for military applications, but is disturbed by low-resolution and noisyrepresentation. In this paper, a recognition method, involving a novel visual attention mechanismbased Gabor region proposal sub-network(Gabor RPN) and improved refinement generative adversarial sub-network(GAN), is proposed. Novel central-peripheral rivalry 3D color Gabor filters are proposed to simulate retinal structures and taken as feature extraction convolutional kernels in low-level layer to improve the recognition accuracy and framework training efficiency in Gabor RPN. Improved refinement GAN is used to solve the problem of blurry target classification, involving a generator to directly generate large high-resolution images from small blurry ones and a discriminator to distinguish not only real images vs. fake images but also the class of targets. A special recognition dataset for ground military target, named Ground Military Target Dataset(GMTD), is constructed. Experiments performed on the GMTD dataset effectively demonstrate that our method can achieve better energy-saving and recognition results when low-resolution and noisy-representation targets are involved, thus ensuring this algorithm a good engineering application prospect.

关键词： Deep learning Biological vision Military application Region proposal network Gabor filter Generative adversarial network

Analysis of phase preservation and interferometric offset test in sparse SAR imaging

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Science China(Information Sciences) 2024年第2期67卷 219-231页

作者： Zhongqiu XU Bingchen ZHANG Guangzuo LI Xueli ZHAN Yanfei BAO Yirong WU Key Laboratory of Spatial Information Processing and Application System Technology Chinese Academy of Sciences Aerospace Information Research Institute Chinese Academy of Sciences school of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of Sciences PLA Academy of Military Sciences

Sparse synthetic aperture radar(SAR) imaging has emerged as a reliable microwave imaging scheme in the recent decade and excels in down-sampling reconstruction and full-sampling performance improvements such as noise, sidelobe, speckle, and ambiguity suppression. To utilize complex image products of sparse reconstruction for improvement in polarimetric, interferometric, and tomographic SAR imaging, it is necessary to evaluate the phase preservation of sparse SAR imaging. In this study, we first introduce the general alternating direction method of multipliers(ADMM) as the universal framework for sparse reconstruction algorithms and adopt chirp scaling algorithm(CSA)-based azimuth-range decouple operators to avoid expensive data storage and processing. Further, we theoretically analyze the phase preservation of the sparse reconstruction algorithm through a comparison with the reconstruction results of CSA. Finally,we conduct the interferometric offset test on the sparse reconstruction results of simulated and real Gaofen-3(GF-3) SAR data, demonstrating the phase-preserving ability of sparse methods.

关键词： sparse SAR imaging phase preservation interferometric offset test general ADMM azimuth-range decouple

Dynamic risk assessment of gas pipeline operation process by fusing visual and olfactory monitoring

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Journal of Safety Science and Resilience 2024年第2期5卷 156-166页

作者： Denglong Ma Weigao Mao Guangsen Zhang Chaoyi Liu Yi Han Xiaoming Zhang Hansheng Wang Kang Cen Wan Lu Denghui Li Hanyue Zhang school of Mechanical Engineering Xi'an Jiaotong UniversityXi'an 710049China Hanzhong Natural Gas Investinent Development Co.Ltd Hanzhong723011China Shaanxi Special Equipment Inspection and Testing Institute Xi'an710038China school of Civil Engineering and Architecture Southwest Petroleum UniversityChengdu610500China Sichuan Tianxin Gas Co.Ltd. Mianyang62100China Petro China Southwest Oil and Gas Field Company Gas Branch Chengdu610500China

With the rapid increase in urban gas consumption,the frequency of maintenance and repair of gas pipelines has escalated,leading to a rise in safety accidents during these *** traditional manual supervision model presents challenges such as inaccurate monitoring results,incomplete risk factor analysis,and a lack of quantitative risk *** research focuses on developing a dynamic risk assessment technology for gas emergency repair operations by integrating the monitoring outcomes of artificial olfactory for gas leakage information and video object recognition for visual safety factor monitoring *** quantitatively evaluate the risk of the operation process,a three-dimensional risk assessment model combining gas leakage with riskcorrelated sensitivity was established as well as a separate three-dimensional risk assessment model integrating visual risk factors with predictable risk ***,a visual risk quantification expression mode based on the risk matrix-radar map method was ***,a risk quantification model based on the fusion of visual and olfactory results was *** verification results of simulation scenarios based on field data indicate that the visual-olfactory fusion risk assessment method can more accurately reflect the dynamic risk level of the operation process compared to simple visual safety factor *** outcomes of this research can contribute to the identification of safety status and early warning of risks related to personnel,equipment,and environmental factors in emergency repair ***,these results can be extended to other operational scenarios,such as oil and gas production stations and long-distance pipeline operations.

关键词： Gas pipelinemaintenance Dynamicriskassessment Visual-olfactoryfusion Risk matrix Risk quantification model

Two‑Dimensional Cr_(5)Te_(8)@Graphite Heterostructure for Efficient Electromagnetic Microwave Absorption

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Nano-Micro Letters 2024年第3期16卷 407-422页

作者： Liyuan Qin Ziyang Guo Shuai Zhao Denan Kong Wei Jiang Ruibin Liu Xijuan Lv Jiadong Zhou Qinghai Shu school of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081People’s Republic of China Centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement(MOE)School of PhysicsBeijing Institute of TechnologyBeijing 100081People’s Republic of China Advanced Research Institute of Multidisciplinary Science Beijing Institute of TechnologyBeijing 100081People’s Republic of China Tangshan Research Institute Beijing Institute of TechnologyTangshan 063099People’s Republic of China

Two-dimensional(2D)transition metal chalcogenides(TMCs)hold great promise as novel microwave absorption materials owing to their interlayer interactions and unique magnetoelectric ***,overcoming the impedance mismatch at the low loading is still a challenge for TMCs due to the restricted loss pathways caused by their high-density ***,an interface engineering based on the heterostructure of 2D Cr_(5)Te_(8) and graphite is in situ constructed via a one-step chemical vapor deposit to modulate impedance matching and introduce multiple attenuation ***,the Cr_(5)Te_(8)@EG(ECT)heterostructure exhibits a minimum reflection loss of up to−57.6 dB at 15.4 GHz with a thin thickness of only 1.4 mm under a low filling rate of 10%.The density functional theory calculations confirm that the splendid performance of ECT heterostructure primarily derives from charge redistribution at the abundant intimate interfaces,thereby reinforcing interfacial polarization ***,the ECT coating displays a remarkable radar cross section reduction of 31.9 dB m^(2),demonstrating a great radar microwave scattering *** work sheds light on the interfacial coupled stimulus response mechanism of TMC-based heterogeneous structures and provides a feasible strategy to manipulate high-quality TMCs for excellent microwave absorbers.

关键词： Chemical vapor deposition Interface polarization engineering Cr_(5)Te_(8)-graphite heterojunctions Microwave absorption