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Wideband radar cross-section reduction by a double-layer-plasma-based metasurface
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作者 赵智明 李小平 +2 位作者 董果香 刘旭 牟相超 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第6期159-168,共10页
Reduction of the radar cross-section(RCS) is the key to stealth technology. To improve the RCS reduction effect of the designed checkerboard metasurface and overcome the limitation of thinlayer plasma in RCS reduction... Reduction of the radar cross-section(RCS) is the key to stealth technology. To improve the RCS reduction effect of the designed checkerboard metasurface and overcome the limitation of thinlayer plasma in RCS reduction technology, a double-layer-plasma-based metasurface—composed of a checkerboard metasurface, a double-layer plasma and an air gap between them—was investigated. Based on the principle of backscattering cancellation, we designed a checkerboard metasurface composed of different artificial magnetic conductor units;the checkerboard metasurface can reflect vertically incident electromagnetic(EM) waves in four different inclined directions to reduce the RCS. Full-wave simulations confirm that the doublelayer-plasma-based metasurface can improve the RCS reduction effect of the metasurface and the plasma. This is because in a band lower than the working band of the metasurface, the RCS reduction effect is mainly improved by the plasma layer. In the working band of the metasurface,impedance mismatching between the air gap and first plasma layer and between first and second plasma layers cause the scattered waves to become more dispersed, so the propagation path of the EM waves in the plasma becomes longer, increasing the absorption of the EM waves by the plasma. Thus, the RCS reduction effect is enhanced. The double-layer-plasma-based metasurface can be insensitive to the polarization of the incoming EM waves, and can also maintain a satisfactory RCS reduction band when the incident waves are oblique. 展开更多
关键词 stealth technology radar cross-section(RCS)reduction backscattering cancellation double-layer-plasma-based metasurface
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RADAR CROSS-SECTION COMPUTATIONS OF ARBITRARILY COMPLICATED TARGETS BY APPLYING THE PANEL METHOD
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作者 周建江 舒永泽 《Journal of Electronics(China)》 1992年第2期140-145,共6页
The present paper deals with the method for the radar cross-section (RCS)computations of arbitrarily complicated targets based on the work by D. Klement et al.(1988).This method is convenient in use, fast in operatio... The present paper deals with the method for the radar cross-section (RCS)computations of arbitrarily complicated targets based on the work by D. Klement et al.(1988).This method is convenient in use, fast in operation and precise in calculating RCS of a complicatedtarget. With this method, the RCS of classic scatterers, for example, a cone and a cylinder, arecomputed with the result of good agreement with experimental data. Furthermore, the RCS’of an aircraft model at various attitudes are calculated with the result of good agreement withexperimental data also. 展开更多
关键词 radar cross-section PANEL method radar target Electromagnetic SCATTERING
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Radar Cross-section Imaging of a Rotating Object with a Multi-frequency Holography
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作者 Zhou Jun, Fang Dagang, Sun Jintao & Sheng Weixing ( Millimeter Wave Tech. Lab., Nanjing University of Science and Technology, 210094, P. R. China ) 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 1997年第1期22-28,共7页
A new method called multi-frequency holography (MFH) for two-dimensional radar cross-section imaging of rotating objects is introduced, in which a constant coherent reference signal from transmitted signal is added in... A new method called multi-frequency holography (MFH) for two-dimensional radar cross-section imaging of rotating objects is introduced, in which a constant coherent reference signal from transmitted signal is added into received signal over certain frequency-width. With the MFH only the intensity of received composite signals needs to be measured. Both imaging situations of far field and near field are considered in details. Special restrictions about the MFH are also discussed and simulated by numerical computation. Examples of numerical simulation show that the method is effective, applicable and perspective. 展开更多
关键词 radar cross-section lmaging Holography.
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An ultra-wideband 2-bit coding metasurface using Pancharatnam–Berry phase for radar cross-section reduction
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作者 Bao-Qin Lin Wen-Zhun Huang +3 位作者 Lin-Tao Lv Jian-Xin Guo Yan-Wen Wang Hong-Jun Ye 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第3期269-275,共7页
An ultra-wideband 2-bit coding metasurface is designed for radar cross-section(RCS) reduction. The design process is presented in detail, in which a polarization conversion metasurface(PCM) is first proposed. The prop... An ultra-wideband 2-bit coding metasurface is designed for radar cross-section(RCS) reduction. The design process is presented in detail, in which a polarization conversion metasurface(PCM) is first proposed. The proposed PCM can realize ultra-wideband circular polarization(CP) maintaining reflection. Moreover, Pancharatnam–Berry(PB) phase will be generated in the co-polarized reflection coefficient by rotating the metallic patches in its unit cells. Thus, based on the PCM, the four coding elements of a 2-bit coding metasurface are constructed using PB phase, and an ultra-wideband PB 2-bit coding metasurface is proposed according to an appropriate coding sequence. The simulated and experimental results show that the coding metasurface has obvious advantages of wideband and polarization-insensitivity. Compared to a metallic plate of the same size, it can achieve more than 10 dB RCS reduction in the frequency band from 9.8 GHz to 42.6 GHz with a relative bandwidth of 125.2% under normal incidence with arbitrary polarizations. 展开更多
关键词 coding metasurface Pancharatnam–Berry phase radar cross-section(RCS)
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Variations in Optical Scattering and Backscattering by Organic and Inorganic Particulates in Chinese Lakes of Taihu, Chaohu and Dianchi 被引量:2
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作者 LYU Heng WANG Qiao +3 位作者 WU Chuanqing ZHU Li LI Yunmei HUANG Jiazhu 《Chinese Geographical Science》 SCIE CSCD 2015年第1期26-38,共13页
This study presents an investigation of the scattering and backscattering properties of the particulates in three Chinese inland lakes(the Taihu Lake, the Chaohu Lake and the Dianchi Lake) based on in situ measurement... This study presents an investigation of the scattering and backscattering properties of the particulates in three Chinese inland lakes(the Taihu Lake, the Chaohu Lake and the Dianchi Lake) based on in situ measurements taken at 119 sites. We modeled the particulate scattering spectra using a wavelength-dependent power-law function, finding that the power-law exponents in the Taihu Lake and the Chaohu Lake differ from those in the Dianchi Lake but are similar to the values in the U.S. coastal waters. In contrast to the open ocean, the backscattering properties in the three lakes can not be determined only from chlorophyll-a concentration. The backscattering ratio spectra exhibit a wavelength dependence feature in all three lakes, generally decreasing with the increasing wavelength. Analysis results of the correlations between the backscattering ratio and the individual water quality parameters clearly show that there are distinctive relations among the three lakes, attributed primarily to different compositions of optically active materials in the three lakes. Analysis of the mass-specific scattering and backscattering coefficients shows that the coefficients at wavelength 532 nm in the Taihu Lake and Chaohu Lake are similar, but they are apparently different from those in the Dianchi Lake. Lastly, Model I multiple linear regressions were adopted to partition the mass-specific cross-sections for scattering and backscattering into organic and inorganic cross-sections to further interpret the scattering and backscattering properties. The relative contribution of organic and inorganic particulates to scattering and backscattering is clearly different among the three lakes. The scattering and backscattering properties of the particulates in the three inland lakes vary significantly based on our collected data. The results indicated that the existing semi-analytical water quality retrieval models of the Taihu Lake can not be applied perfectly to the Chaohu Lake and the Dianchi Lake. 展开更多
关键词 scattering/backscattering coefficient backscattering ratio mass-specific cross-section organic/inorganic particulates Chinese inland lakes
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IR LASER BACKSCATTERING FROM AN ARBITRARILY SHAPED DIELECTRIC OBJECT WITH ROUGH SURFACE 被引量:4
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作者 吴振森 《Journal of Electronics(China)》 1993年第4期298-306,共9页
The backscattering of light wave from arbitrarily convex dielectric objects withrough surface is investigated and formulas for calculating the backscattering cross-section of bothcoherent and incoherent fields are obt... The backscattering of light wave from arbitrarily convex dielectric objects withrough surface is investigated and formulas for calculating the backscattering cross-section of bothcoherent and incoherent fields are obtained.In the infrared wave-band,the influence of the ge-ometry,permittivity and statistical characteristics of the rough surface on LRCS is analyzed,byusing rough sphere and ellipsoids as examples. 展开更多
关键词 Infrared LASER LRCS(Laser radar(scattering)cross-section) ROUGHNESS
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Backscattering by sea of centimeter and millimeter waves at small grazing angle 被引量:1
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作者 V F Kravchenko V I Lutsenko I V Lutsenko 《Journal of Measurement Science and Instrumentation》 CAS 2014年第2期36-43,共8页
Using experimental data reflected by the sea on specific radar cross-section (SRCS) at millimeter and centimeter waves, the approximations of the wind speed, angle of the sea surface radiation and polarization of th... Using experimental data reflected by the sea on specific radar cross-section (SRCS) at millimeter and centimeter waves, the approximations of the wind speed, angle of the sea surface radiation and polarization of the incident field can be calculated. The simulation model of the scattered signal has been proposed on the basis of the semi-Markov nested processes. For the first time it has been proved that for the description of reflections at spikes and pauses, it is possible to use finite atomic functions. The proposed model allows us to estimate the baekscatter intensity of millimeter and centimeter radio waves by the sea at grazing angle of surface radiation, as well as to simulate scattered signal. 展开更多
关键词 radar cross-section sea surface centimeter and millimeter waves semi-Markov process atomic function
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Reconstruction Parameters of Local Scattering Sources of a Metallic Strip from the Backscattering Pattern
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作者 Stanislav N. Kutishchev 《Journal of Electromagnetic Analysis and Applications》 2012年第12期492-496,共5页
In this paper, it is proved the ability of quantity reconstruction, amplitudes and coordinates of metallic strip local scattering sources from the backscattering pattern. They are performed as the results of numerical... In this paper, it is proved the ability of quantity reconstruction, amplitudes and coordinates of metallic strip local scattering sources from the backscattering pattern. They are performed as the results of numerical solution for the infinite perfect conducting strip in case of E-polarization of the incident plane electromagnetic wave. In this case it is necessary to fulfill the following conditions. The local sources amplitudes should be the same order, in transverse and longitudinal directions the local sources should be separated into distances more than apparatus resolution, and the object maximum size does not have to be more than approximately 50λ. It was shown the limit and ability of the further development of the offered method. 展开更多
关键词 backscattering PATTERN Local SCATTERING SOURCES radar Image Electromagnetic Wave Method METALLIC STRIP
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利用Radarsat-2数据基于比值检测的水稻制图 被引量:6
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作者 化国强 李晨 +2 位作者 杨沈斌 葛道阔 李秉柏 《江苏农业学报》 CSCD 北大核心 2012年第6期1451-1458,共8页
利用2010年获取的2景Radarsat-2全极化SAR数据,探讨水稻及其他地物在不同时相上的后向散射特征差异,并提出在雷达遥感图像上基于比值检测理论的水稻分类制图方法。通过分析研究区内水稻、茭白等主要地物在2个时相上不同极化方式下的后... 利用2010年获取的2景Radarsat-2全极化SAR数据,探讨水稻及其他地物在不同时相上的后向散射特征差异,并提出在雷达遥感图像上基于比值检测理论的水稻分类制图方法。通过分析研究区内水稻、茭白等主要地物在2个时相上不同极化方式下的后向散射特征,利用比值检测理论建立水稻及其他地物像元概率分布及分布函数并计算出主要地物的分类阈值,在剔除茭白的影响下,完成水稻的分类制图。水稻和茭白作为水生作物具有明显的雷达图像表现特征;在HH/VV比值图像中,分类阈值1.393对水稻的识别最好,制图精度达到92.64%,总误差概率为7.74%。研究结果表明,Radarsat-2数据在水稻监测中具有丰富多样的技术手段以及更为广泛的应用潜力。 展开更多
关键词 分类阈值 后向散射 水稻制图 雷达遥感
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Coastal wind field retrieval from polarimetric synthetic aperture radar 被引量:3
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作者 ZHANG Yi JIANG Xingwei +2 位作者 SONG Qingtao LIN Mingsen XIE Xuetong 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2014年第5期54-61,共8页
Coastal winds are strongly influenced by topology and discontinuity between land and sea surfaces. Wind assessment from remote sensing in such a complex area remains a challenge. Space-borne scatterometer does not pro... Coastal winds are strongly influenced by topology and discontinuity between land and sea surfaces. Wind assessment from remote sensing in such a complex area remains a challenge. Space-borne scatterometer does not provide any information about the coastal wind field, as the coarse spatial resolution hampers the radar backscattering. Synthetic aperture radar (SAR) with a high spatial resolution and all-weather observation abilities has become one of the most important tools for ocean wind retrieval, especially in the coastal area. Conventional methods of wind field retrieval from SAR, however, require wind direction as initial information, such as the wind direction from numerical weather prediction models (NWP), which may not match the time of SAR image acquiring. Fortunately, the polarimetric observations of SAR enable independent wind retrieval from SAR images alone. In order to accurately measure coastal wind fields, this paper proposes a new method of using co-polarization backscattering coefficients from polarimetric SAR observations up to polarimetric correlation backscattering coefficients, which are acquired from the conjugate product of co-polarization backscatter and cross-polarization backscatter. Co-polarization backscattering coefficients and polarimetric correlation backscattering coefficients are obtained form Radarsat-2 single-look complex (SLC) data.The maximum likelihood estimation is used to gain the initial results followed by the coarse spatial filtering and fine spatial filtering. Wind direction accuracy of the final inversion results is 10.67 with a wind speed accuracy of 0.32 m/s. Unlike previous methods, the methods described in this article utilize the SAR data itself to obtain the wind vectors and do not need external wind directional information. High spatial resolution and high accuracy are the most important features of the method described herein since the use of full polarimetric observations contains more information about the space measured.This article is a useful addition to the work of independent SAR wind retrieval. The experimental results herein show that it is feasible to employ the co-polarimetric backscattering coefficients and the polarimetric correlation backscattering coefficients for coastal wind field retrieval. 展开更多
关键词 polarimetric synthetic aperture radar coastalwind field polarimetric correlation backscattering coefficients
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MONOSTATIC RADAR CROSS SECTION FOR REFLECTOR ANTENNAS 被引量:1
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作者 邓书辉 阮颖铮 《Journal of Electronics(China)》 1991年第1期28-35,共8页
The calculation formulas of monostatic radar cross-section (RCS) of arbitrary re-flectors with arbitrarily polarized plane-wave incidence are derived, where the spicular field isobtained by geometrical optics (GO) and... The calculation formulas of monostatic radar cross-section (RCS) of arbitrary re-flectors with arbitrarily polarized plane-wave incidence are derived, where the spicular field isobtained by geometrical optics (GO) and the edge-diffracted field is calculated by the method ofequivalent currents (MEC). Some typical calculated results are given by means of RCS spatialgraphs. For both horizontal and vertical polarizations, the theoretical results obtained in thispaper agree very well with the experimental results as well as the results from uniform theory ofdiffraction. 展开更多
关键词 ANTENNA radar cross-section ELECTROMAGNETIC SCATTERING
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Investigation into wideband electromagnetic stealth device based on plasma array and radar-absorbing materials
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作者 Xuesong DENG Chenglong DING +5 位作者 Yahui WANG Zhigang LI Li CHENG Zongsheng CHEN Xiangyin LV Jiaming SHI 《Plasma Science and Technology》 SCIE EI CAS CSCD 2022年第11期54-62,共9页
Manipulation of electromagnetic waves is essential to various microwave applications,and absorbing devices composed of low-pressure gas discharge tubes and radar-absorbing materials(RAM)can bring new solutions to broa... Manipulation of electromagnetic waves is essential to various microwave applications,and absorbing devices composed of low-pressure gas discharge tubes and radar-absorbing materials(RAM)can bring new solutions to broadband electromagnetic stealth.The microwave transmission method is used to measure the physical parameters of the plasma unit.The designed structure exhibits superior absorption performance and radar cross-section(RCS)reduction capability in the 2–18 GHz band,with unique absorption advantage in the S and C frequency bands.It is found that the combination of the plasma and the RAM can significantly broaden the absorption frequency band and improve the absorption performance with excellent synergistic stealth capability.Experimental and simulation results present that broadband,wide-angle,tunable electromagnetic wave absorption and RCS reduction can be achieved by adjusting the spatial layout of the combined plasma layer and the type of RAMs,which creates opportunities for microwave transmission and selective stealth of equipment.Therefore,the wave manipulation by combined plasma array and RAM provides a valuable reference for developing numerous applications,including radar antenna stealth,spatial filter,and high power microwave shielding. 展开更多
关键词 radar stealth plasma stealth radar cross-section ABSORBER
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FY-3G降水测量雷达海洋定标精度检验与评估
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作者 袁梅 尹红刚 +4 位作者 商建 江柏森 杨润峰 谷松岩 张鹏 《应用气象学报》 CSCD 北大核心 2024年第5期526-537,共12页
2023年4月发射的风云三号气象卫星G星(FY-3G)是我国首颗专用降水测量卫星,双频降水测量雷达(precipitation measurement radar,PMR)是该颗卫星上最核心的仪器。基于2023年7月数据,利用海洋定标理论模型,模拟海洋表面后向散射截面,与观... 2023年4月发射的风云三号气象卫星G星(FY-3G)是我国首颗专用降水测量卫星,双频降水测量雷达(precipitation measurement radar,PMR)是该颗卫星上最核心的仪器。基于2023年7月数据,利用海洋定标理论模型,模拟海洋表面后向散射截面,与观测海洋表面后向散射截面进行比对,实现对PMR定标精度的初步评估。通过与国外星载双频降水测量雷达(global precipitation measurement,dual-frequency precipitation radar,GPM DPR)海洋定标检验结果比对,评估FY-3G PMR定标的准确性。海洋定标精度检验结果表明:FY-3G PMR Ku波段在入射角小于15°时观测值与模型模拟值的偏差较小,此时FY-3G PMR的偏差为1.65~2.73 dB,偏差标准差为0.74~1.82 dB。FY-3G PMR Ka波段在18°入射角时偏差小于0.27 dB,偏差的标准差为3.49 dB。FY-3G PMR与GPM DPR的定标偏差存在较为固定的偏差,差异主要源自于数据本身的后向散射统计特性,各入射角下FY-3G PMR Ku与Ka波段海洋表面后向散射数据稳定性与GPM DPR相当。 展开更多
关键词 降水测量雷达 FY-3G 后向散射截面 海洋定标 精度检验
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基于双频段雷达高度计数据的海面阵风反演研究
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作者 林静 张有广 《海洋学报》 CAS CSCD 北大核心 2024年第4期133-142,共10页
海面阵风是海洋资源开发、海洋防灾减灾和海洋科研等领域所需的重要海洋动力环境信息。但迄今为止,海面阵风观测数据严重缺失,阻碍了阵风预报、应用研究等方面的发展。本文利用双频的HY-2B卫星高度计C、Ku波段的后向散射系数,对现有海... 海面阵风是海洋资源开发、海洋防灾减灾和海洋科研等领域所需的重要海洋动力环境信息。但迄今为止,海面阵风观测数据严重缺失,阻碍了阵风预报、应用研究等方面的发展。本文利用双频的HY-2B卫星高度计C、Ku波段的后向散射系数,对现有海面风速(U_(10))进行修正,建立了阵风风速(U_(g))反演算法。反演结果与美国国家浮标数据中心(NDBC)2018-2022年的浮标数据进行真实性检验,相关系数(R)为0.91,均方根误差(RMSE)为1.82 m/s;国外同类卫星Jason-3基于本方法的反演结果与2018-2022年NDBC站点数据进行检验,RMSE优于常规2 m/s精度要求;反演结果与处于不同纬度的近海远洋站点进行个例验证,RMSE均优于2 m/s。因此,本文在现有的HY-2B卫星高度计海面风速观测数据的基础上,利用不同波段信息实现了海面阵风的观测,具有较高的观测精度。同时,该方法也适用于相同观测体制的国外卫星高度计。 展开更多
关键词 雷达高度计 反演算法 海面阵风 HY-2B卫星 后向散射系数
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Improvement of a 3D radar backscattering model using matrix-doubling method 被引量:4
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作者 NI WenJian1,2, GUO ZhiFeng1 & SUN GuoQing3 1 State Key Laboratory of Remote Sensing Science, jointly sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101, China 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China 3 Department of Geography, University of Maryland, College Park, MD 27042, USA 《Science China Earth Sciences》 SCIE EI CAS 2010年第7期1029-1035,共7页
Radiative transfer models have been widely used to simulate the radar backscattering from forested areas. A three-dimensional radar backscatter model of forest canopy developed in previous studies takes full account o... Radiative transfer models have been widely used to simulate the radar backscattering from forested areas. A three-dimensional radar backscatter model of forest canopy developed in previous studies takes full account of spatial position of trees in a forest stand, and the interactions among crown, trunk and ground surface. The model predicted well for the co-polarized backscatter measurements, but underestimated the backscattering for cross-polarization, primarily because only the first-order scattering within tree crowns was considered in the model. The backscattering at cross-polarization depends strongly on multiple scatter- ing within tree crowns. To produce good estimations for cross-polarized component, the matrix-doubling method is employed here to compute multiple-scattering within the crown. The modified model is compared with the original model, and the field forest measurements and AIRSAR data are used for validation of the modified model. The cross-polarization backscattering is improved in different degrees for different crown structures and at different bands. 展开更多
关键词 REMOTE sensing FORESTRY ELECTROMAGNETIC PROPAGATION radar backscattering model matrix-doubling
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基于空分天线的雷达大气目标探测技术研究
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作者 王斯正 任雍 +2 位作者 陈俊 周亭亭 卫楠 《无线电工程》 2024年第11期2624-2632,共9页
为了拓展新型中间层-平流层-对流层(Mesosphere-Stratosphere-Troposphere, MST)雷达测风工作模式,提高测风数据的时间分辨力,基于全相关分析(Full Correlation Analysis, FCA)方法与大气散射模型,设计了一种应用于MST雷达的空分天线(Sp... 为了拓展新型中间层-平流层-对流层(Mesosphere-Stratosphere-Troposphere, MST)雷达测风工作模式,提高测风数据的时间分辨力,基于全相关分析(Full Correlation Analysis, FCA)方法与大气散射模型,设计了一种应用于MST雷达的空分天线(Spaced-Antenna, SA)测风模式。通过大气散射模型结合雷达实际阵面分布与工作参数产生仿真时域信号,讨论了不同相关函数、相关函数拟合方法以及MST雷达不同天线尺度对雷达测风结果的影响。为验证测风模式的有效性,将信噪比(Signal to Noise Ratio, SNR)不同的测风结果与模型中风场真值进行比较。研究结果表明,新的测风模式仿真计算得到的风速、风向结果精度较高,符合雷达实际探测要求。 展开更多
关键词 空分天线模式 全相关分析 大气散射模型 中间层-平流层-对流层雷达 风场测量
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Construction of enhanced multi-polarization and high performance electromagnetic wave absorption by self-growing ZnFe_(2)O_(4)on Cu_(9)S_(5)
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作者 Wenxiong Chen Honglong Xing 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第8期1922-1934,共13页
The development of 3D structural composites with electromagnetic(EM)wave absorption could attenuate EM waves.Herein,magnetized flower-like Cu_(9)S_(5)/ZnFe_(2)O_(4)composites were fabricated through a multistep hydrot... The development of 3D structural composites with electromagnetic(EM)wave absorption could attenuate EM waves.Herein,magnetized flower-like Cu_(9)S_(5)/ZnFe_(2)O_(4)composites were fabricated through a multistep hydrothermal method.The crystallographic and surface phase chemical information,morphological structure,and magnetic and EM parameters of the composites were analyzed.The prepared Cu_(9)S_(5)/ZnFe_(2)O_(4)composites have multiple loss paths for EM waves and present an overall 3D flower-like structure.The Cu_(9)S_(5)/ZnFe_(2)O_(4)composites exhibit a minimum reflection loss of-54.38 dB and a broad effective absorption bandwidth of 5.92 GHz.Through magnetization,ZnFe_(2)O_(4)particles are self-assembled and grown on the surfaces of Cu_(9)S_(5).Such a modification is conducive to the generation of additional cross-linking contact sites and the effective introduction of a large number of phase interfaces,crystalline defects,special three-dimensional flower-like structures,and magneto-electrical coupling loss effects.Moreover,the synergistic effect of multiple loss strategies effectively improves EM wave absorption by the material.This work can provide a strategy for the use of magnetizationmodified sulfide composite functional materials in EM wave absorption. 展开更多
关键词 self-assembled material electromagnetic wave absorption enhanced multi-polarization effect Cu_(9)S_(5)/ZnFe_(2)O_(4)composites radar cross-section
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单时相双极化ENVISAT ASAR数据水稻识别 被引量:34
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作者 谭炳香 李增元 +1 位作者 李秉柏 张平平 《农业工程学报》 EI CAS CSCD 北大核心 2006年第12期121-127,F0004,共8页
许多研究已表明合成孔径雷达(SAR)对水稻识别及作物长势监测很有潜力。但是,以往的研究多是采用单极化多时相SAR数据进行水稻监测的。该文本着探讨多极化方式的优势以及降低数据购买成本和减少数据处理量的目的,对单时相双极化的ENV ISA... 许多研究已表明合成孔径雷达(SAR)对水稻识别及作物长势监测很有潜力。但是,以往的研究多是采用单极化多时相SAR数据进行水稻监测的。该文本着探讨多极化方式的优势以及降低数据购买成本和减少数据处理量的目的,对单时相双极化的ENV ISAT A SAR APP数据的水稻识别能力进行了评价。在水稻生长季节,获取了覆盖江苏洪泽县的A SAR APP时间序列数据。首先,分析比较不同地物的后向散射系数,选择出最能区分水稻与非水稻的单时相数据;然后,采用决策阈值法将水稻信息从图像中提取出来;最后,利用DGPS实测的样地数据对水稻识别进行精度验证。结果表明,利用水稻齐穗期至近成熟期的HH和VV极化的ENV ISAT A SAR APP图像能较好区分水稻与非水稻,水稻识别精度可达86%以上。 展开更多
关键词 ENVISAT ASAR 水稻 双极化 雷达后向散射
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基于激光雷达技术的输电线路山火监测方法 被引量:12
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作者 陈锡阳 杨挺 +4 位作者 尹创荣 沈秀斌 谢从珍 戴栋 张敏 《激光与红外》 CAS CSCD 北大核心 2014年第11期1202-1206,共5页
针对现有架空输电线路通道山火监测方法的不足,基于激光雷达技术,提出采用激光雷达系统对输电线路通道引发的山火进行监测。通过在距离监测点560 m、460 m、360 m及260 m处分别进行激光雷达系统监测烟雾的模拟实验,实验结果充分验证了... 针对现有架空输电线路通道山火监测方法的不足,基于激光雷达技术,提出采用激光雷达系统对输电线路通道引发的山火进行监测。通过在距离监测点560 m、460 m、360 m及260 m处分别进行激光雷达系统监测烟雾的模拟实验,实验结果充分验证了该系统可实现对线路周边区域引发的山火状态进行宽范围、较高精度的监测和评估,为输电线路的安全运行和维护提供决策信息,进而能够提高整个输电网络的供电可靠性,降低输电通道的山火事故发生率。 展开更多
关键词 激光雷达 山火 后向散射系数 监测
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水稻时域散射特征分析及其应用研究 被引量:42
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作者 邵芸 郭华东 +1 位作者 范湘涛 刘浩 《遥感学报》 EI CSCD 北大核心 2001年第5期340-345,共6页
通过对肇庆试验区 1996年和 1997年获取的多时相、多模式雷达卫星 (RADARSAT)数据分析 ,从图像上直接提取地物的后向散射系数 ,结合实地测量水稻的生长结构参数 ,建立了水稻生长模型 ,分析了不同生长周期 (从 80天到 12 0— 12 5天 ) 4... 通过对肇庆试验区 1996年和 1997年获取的多时相、多模式雷达卫星 (RADARSAT)数据分析 ,从图像上直接提取地物的后向散射系数 ,结合实地测量水稻的生长结构参数 ,建立了水稻生长模型 ,分析了不同生长周期 (从 80天到 12 0— 12 5天 ) 4种类型水稻的时域散射特性。利用 1997年 4月至 7月获取的 7景标准模式雷达卫星数据 ,对试验区内三个县和两个行政区共 5 0 0 0km2 面积范围内的作物进行分类和水稻产量预估算 ,水稻类型分类及面积量算精度达 91%。结果表明 :利用雷达遥感数据进行水稻种植面积量算和估产需要水稻生长期间三个时相的数据 ,即插秧期、抽穗期、收割前期。若能够获得多参数雷达图像 ,可以用插秧期和收割前期的两个时相图像来代替上述的三个时相图像同样可以达到种植面积量算和估产的效果。这一结果充分说明多时相雷达卫星数据对我国南方水稻长势监测及估产具有明显优势和潜力。 展开更多
关键词 雷达遥感 后向散射系数 水稻 时域分析 估产 图像处理 生长结构
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