共查询到20条相似文献,搜索用时 31 毫秒
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随着隐形技术的迅猛发展,处于战争中的任何军事目标都面临着巨大的威胁,从而使得反隐形成为一项紧迫的任务和要求。文中介绍了隐形平台的隐形原理及其存在缺陷,从其缺陷出发针对性地阐述了雷达反隐形技术,同时介绍了几种具有反隐形功能的雷达,包括双基地雷达、相控阵雷达、超宽带雷达、激光雷达、米波雷达和等离子雷达、合成孔径雷达的反隐形原理。 相似文献
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激光雷达截面在系统设计评价中的应用分析 总被引:6,自引:0,他引:6
讨论分析了激光雷达截面在激光测量系统设计评价中的应用.分析了激光雷达截面的物理意义,给出了目标激光雷达截面的计算、测量原理与方法,从激光雷达截面的理论定义出发,推导出普遍适用于各类激光测量系统和各种散射特性目标的基本测量方程,该方程利用激光雷达截面表征目标的激光散射特性.通过典型实例说明了该方程在激光测量系统设计评价中的应用.与其他用于表征目标激光散射特性的指标相比,激光雷达截面更容易通过计算或测量得到,且更适用于复杂散射特性目标,因此,在激光测量系统的设计评价中应采用由目标激光雷达截面表述的激光测量方程. 相似文献
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Actively mode-locked 26 ps optical pulses are generated from a gain-guided, 10-stripe, phased laser GaAs diode array with an external cavity consisting of two cylindrical lenses and a corner reflector. To our knowledge, this is the shortest pulse width yet demonstrated from a mode-locked phased laser diode array. The detuning bandwidth of the mode-locking is measured as 2.5 MHz.<> 相似文献
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Calibration of a polarimetric imaging SAR 总被引:2,自引:0,他引:2
Sarabandi K. Pierce L.E. Ulaby F.T. 《Geoscience and Remote Sensing, IEEE Transactions on》1992,30(3):540-549
Calibration using point targets is discussed. The fourport network calibration technique is used to describe the radar error model. The processor ambiguity function and the radar distortion matrices are combined to form a generalized polarimetric ambiguity function. The polarimetric ambiguity function of the SAR is found using a single point target, namely a trihedral corner reflector. Based on the resultant polarimetric ambiguity function, an estimate for the backscattering coefficient of the terrain is found using a modified version of the single target calibration technique (STCT). A radar image recorded by the JPL aircraft SAR, which includes a variety of point targets, is used for verification of the new calibration method. The calibrated responses of the point targets are compared both with theory and responses based on the POLCAL technique 相似文献
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针对电子干扰和隐身目标的威胁日趋恶化的趋势,本文研究了电子对抗环境下T/R-R型双基地雷达如何运用数据融合实现对隐身目标的三维跟踪问题.按照无-弱-较强-强的干扰强度变化,提出了双基地雷达采取不同观测子集对隐身目标的跟踪技术,对不同干扰方式下双基地雷达对隐身目标的测量误差以及双基地雷达截面积的计算进行了讨论,建立了电子战环境下双基地雷达对隐身目标的测量模型,给出了几种典型情况下的计算机仿真结果,验证了双基地雷达反隐身的有效性. 相似文献
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Unal C.M.H. Niemeijer R.J. van Sinttruyen J.S. Ligthart L.P. 《Geoscience and Remote Sensing, IEEE Transactions on》1994,32(4):837-845
Based on the existing mathematical formalisms of radar polarimetry, it is necessary to perform accurate and diversified polarimetric measurements in the real world to thoroughly investigate signature definition, identification, and classification of radar targets. For this study the Delft Atmospheric Research Radar (DARR) is used. This ground-based polarimetric FM-CW radar operates in the S-band. The purpose of the present paper is the polarimetric calibration of the DARR. Among the passive reflectors, a rotatable dihedral corner reflector is a suitable calibration object. It enables one to measure different scattering matrices with only one reflector. One alignment must be performed and the scattering matrices are measured at the same range. By measuring several scattering matrices, the accuracy of the calibration result can be estimated. A measurement campaign with a rotatable dihedral corner reflector was therefore performed. The experimental results and the calibration procedure are presented in this paper 相似文献
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Qi Yang Bin Deng Hongqiang Wang Yuliang Qin 《Journal of Infrared, Millimeter and Terahertz Waves》2017,38(7):909-928
Rotation is one of the typical micro-motions of radar targets. In many cases, rotation of the targets is always accompanied with vibrating interference, and it will significantly affect the parameter estimation and imaging, especially in the terahertz band. In this paper, we propose a parameter estimation method and an image reconstruction method based on the inverse Radon transform, the time-frequency analysis, and its inverse. The method can separate and estimate the rotating Doppler and the vibrating Doppler simultaneously and can obtain high-quality reconstructed images after vibration compensation. In addition, a 322-GHz radar system and a 25-GHz commercial radar are introduced and experiments on rotating corner reflectors are carried out in this paper. The results of the simulation and experiments verify the validity of the methods, which lay a foundation for the practical processing of the terahertz radar. 相似文献
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A synthetic aperture at optical frequencies 总被引:1,自引:0,他引:1
Synthetic aperture radar principles are employed to resolve targets within the beam of a helium-neon laser. Reflections from closely spaced targets moving simultaneously through a laser beam are detected in the presence of a reference beam. The resulting signals are stored on film and subsequently processed to reconstruct the target images. 相似文献
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RCS analysis and reduction for lossy dihedral corner reflectors 总被引:3,自引:0,他引:3
Griesser T. Balanis C.A. Liu K. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1989,77(5):806-814
The radar cross-section patterns of lossy dihedral corner reflectors are calculated using a uniform geometrical theory of diffraction for impedance surfaces. All terms of up to third order reflections and diffractions are considered for patterns in the principal plane. The surface waves are included whenever they exist for reactive surface impedances. The dihedral corner reflectors examined have right, obtuse, and acute interior angles, and patterns over the entire 360° azimuthal plane are calculated. The surface impedances can be different on the four faces of the dihedral corner reflector; however, the surface impedance must be uniform over each face. Computed cross sections are compared with a moment method technique for a dielectric/ferrite absorber coating on a metallic corner reflector. The analysis of the dihedral corner reflector is important because it demonstrates many of the important scattering contributors of complex targets including both interior and exterior wedge diffraction, half-plane diffraction, and dominant multiple reflections and diffractions 相似文献
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基于组合矩的激光成像雷达目标识别算法 总被引:2,自引:0,他引:2
随着激光技术的发展,激光成像雷达在现代战争复杂战场环境中逐渐获得了广泛的应用,目前激光成像雷达自动目标识别技术已成为国内外研究的热点问题。提出了基于组合矩的激光成像雷达目标识别算法,从激光成像雷达目标的距离像中提取低阶的Zernike矩、Hu矩和中心矩构成组合矩特征,该特征对距离像噪声不敏感,应用径向基函数(RBF)神经网络对三种地面目标进行分类识别。实验结果表明,该算法与应用Zernike矩和Hu矩特征进行分类识别相比,对三种激光成像雷达地面目标的平均识别率在高载噪比(20dB)下分别提高了1.0%和3.7%;在低载噪比(10dB)下分别提高了11.8%和42.5%;当载噪比高于17dB时,该算法的平均识别率达到100%。因此该算法取得了比较好的识别效果。 相似文献
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隐身进攻武器威胁及光电对抗研究 总被引:2,自引:0,他引:2
采用隐身技术和低可见性技术的隐身进攻武器并非不可探测 ,其中采用常规的长波低频雷达可以探测低可见性威胁目标 ,采用激光雷达技术、光电探测技术和雷达组网技术等均具有探测隐身目标的能力。 相似文献
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Eldada L. Scarmozzino R. Osgood R.M. Jr. Scott D.C. Chang Y. Fetterman H.R. 《Lightwave Technology, Journal of》1995,13(10):2034-2040
We have used laser direct fabrication techniques to implement optical delay lines on an epitaxial GaAs/AlGaAs substrate. These integrated photonic circuits, which are important for optically-controlled phased-array radar, include asymmetric splitters with various splitting ratios, smoothly curved 90° bends, as well as linear waveguides. The delay lines were tested and found to have the desired delay and a power-output uniformity of ±2-4% 相似文献
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Sarabandi K. Pierce L.E. Dobson M.C. Ulaby F.T. Stiles J.M. Chiu T.C. De Roo R. Hartikka R. Zambetti A. Freeman A. 《Geoscience and Remote Sensing, IEEE Transactions on》1995,33(4):858-866
In preparation for the Shuttle Imaging Radar-C/XSAR (SIR-C/XSAR) flights, the University of Michigan has been involved in the development of calibration procedures and precision calibration devices to quantify the complex radar images with an accuracy of 0.5 dB in magnitude and 5 degrees in phase. In this paper, the preliminary results of the SIR-C calibration and a summary of the University of Michigan's activity in the Raco calibration super-site is presented. In this calibration campaign an array of point calibration targets including trihedral corner reflectors and polarimetric active radar calibrators (PARCs) in addition to a uniform distributed target were used for characterizing the radiometric calibration constant and the distortion parameters of the C-band SAR. Two different calibration methods, one based on the application of point targets and the other based on the application of the distributed target, are used to calibrate the SIR-C data and the results are compared with calibrated images provided by JPL. The distributed target used in this experiment was a field of grass, sometimes covered with snow, whose differential Mueller matrix was measured immediately after the SIR-C overpass using The University of Michigan polarimetric scatterometer systems. The scatterometers were calibrated against a precision metallic sphere and measured 100 independent spatial samples for characterizing the differential Mueller matrix of the distributed target to achieve the desired calibration accuracy. The L-band SAR has not yet been adequately calibrated for inclusion here 相似文献