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1.
Polarimetric radar interferometry for improved mine detection andsurface clutter rejection 总被引:1,自引:0,他引:1
Sagues L. Lopez-Sanchez J.M. Fortuny J. Fabregas X. Broquetas A. Sieber A.J. 《Geoscience and Remote Sensing, IEEE Transactions on》2001,39(6):1271-1278
A recently developed technique, polarimetric radar interferometry, is applied to tackle the problem of the detection of buried objects embedded in surface clutter. An experiment with a fully polarimetric radar in an anechoic chamber has been carried out using different frequency bands and baselines. The processed results show the ability of this technique to detect buried plastic mines and to measure their depth. This technique enables the detection of plastic mines even if their backscatter response is much lower than that of the surface clutter 相似文献
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A novel signal processing technique for clutter reduction in GPR measurements of small, shallow land mines 总被引:12,自引:0,他引:12
van der Merwe A. Gupta I.J. 《Geoscience and Remote Sensing, IEEE Transactions on》2000,38(6):2627-2637
A signal processing technique is developed to reduce clutter due to ground bounce in ground penetrating radar (GPR) measurements. This technique is especially useful when a GPR is used to detect subsurface antipersonnel mines. The GPR clutter is modeled using a simple parametric model. Buried mine and clutter contributions are separated through a pair of coupled iterative procedures. The algorithm outperforms existing clutter reduction approaches and also yields target features that are useful for detection and identification of these mines. The proposed technique effectively reduces clutter resulting in a significant decrease in false alarm rates. 相似文献
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Experimental and theoretical results are presented for ultra wide-band (UWB) synthetic aperture radar (SAR) signatures of buried anti-tank and anti-personnel mines. Such are characterized by resonance-like peaks as well as valleys, across the 50-1200 MHz bandwidth considered. Consequently, frequency subbanding is used to highlight one target over another, of application to discriminating targets (mines) from clutter 相似文献
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Experimental model for a seismic landmine detection system 总被引:1,自引:0,他引:1
Scott W.R. Jr. Martin J.S. Larison G.D. 《Geoscience and Remote Sensing, IEEE Transactions on》2001,39(6):1155-1164
A laboratory-scale experimental model has been developed and tested for a system that uses artificially generated high-frequency seismic waves in conjunction with a radar-based noncontact displacement sensor to detect buried landmines. The principle of operation of the system is to measure the transient displacement field very close to a mine location. In this way, the absorption and the geometrical spreading of the seismic waves have not reduced the effects of the mine. By using a seismic excitation, the system exploits the large difference between the elastic properties of a mine and the surrounding soil. This difference causes seismic wave interactions in the vicinity of a mine to be quite distinctive and provides a method for imaging mines and distinguishing them from typical buried clutter. Images of a variety of simulated and inert anti-tank and anti-personnel mines have been formed using this system. Burial scenarios involving natural clutter (rocks and sticks), light surface vegetation, localized burial effects, and multiple mines in close proximity have been studied. None of these scenarios appears to pose serious problems for detection performance 相似文献
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The passive infrared (IR) imaging signature of buried mines under three different soil surface conditions is investigated in this work. The three-dimensional (3-D) nature of the mine, the site, and the temporal attributes of surrounding climate and exposed radiation are accounted for with large and moderate-scale clutter surfaces as well as a smooth surface. The effect of the short- and long-wavelength radiation as well as the convective heat transfer is incorporated in this analysis and the temporal development of the temperature distribution over a diurnal cycle is presented for different surface conditions. The occurrence of false alarm mine spots is demonstrated using the moderate scale clutter surface and a critical period of time for the landmine signature is established for different soil surface conditions. The present results show that mines buried at moderate depths in the soil would not produce a direct signature 相似文献
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Resistively loaded Vee dipoles are considered for use in a short-pulse ground penetrating radar (GPR) used to detect buried antipersonnel land mines. First, a study is made to select a short pulse to radiate that is most appropriate for the problem. A simple one-dimensional (1-D) analysis of some representative soils and a land mine is used to select a radiated pulse similar in shape to a differentiated Gaussian pulse with a spectral peak at 4 GHz. Based on previous studies, the conductivity of the arms of the Vee dipole is linearly tapered from the feed to the open ends. A fully three-dimensional (3-D) finite-difference time domain (FDTD) model is developed and used to simulate the GPR land mine detection problem. Using this model, a resistively loaded Vee dipole is selected and evaluated. Parametric studies related to the problem are conducted including: varying the height of the Vee above the ground, varying the position of the land mine both laterally and in depth, and examining the effects of the geometry of the land mine on the received signal. Environmental conditions are examined including signal returns from rocks and variations in the shape of the surface of the ground. The FDTD results are validated by comparisons with experimental data. These studies demonstrate that resistively loaded Vee dipoles can greatly reduce clutter related to the antenna, making the task of distinguishing land mines (targets) much easier 相似文献
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Carin L. Geng N. McClure M. Sichina J. Lam Nguyen 《Antennas and Propagation Magazine, IEEE》1999,41(1):18-33
A full-wave model is developed for electromagnetic scattering from buried and surface land mines (both conducting and plastic), taking rigorous account of the lossy, dispersive, and potentially layered properties of soil. The (polarimetric) theoretical results are confirmed via synthetic-aperture radar (SAR) measurements, performed using the US Army Research Laboratory's BoomSAR, with which fully polarimetric ultra-wide-band (50-1200 MHz) SAR imagery is produced. The SAR system is used to acquire a large database of imagery, including a significant distribution of naturally occurring clutter. Several techniques are used for mine detection with such data, including several detectors that are based on target features gleaned from the modeling, as well as a matched-filter-like detector that directly incorporates the target signatures themselves. In addition, the theoretical model is used to predict wave phenomenology in various environments (beyond the limited range of parameters that can be examined experimentally). Since the efficacy of radar-based subsurface sensing depends strongly on the soil properties, we perform a parametric study of the dependence of such on the target RCS, and on possible landmine resonances 相似文献
10.
Advanced polarimetric subsurface FM-CW radar 总被引:2,自引:0,他引:2
Moriyama T. Kasahara H. Yamaguchi Y. Yamada H. 《Geoscience and Remote Sensing, IEEE Transactions on》1998,36(3):725-731
The subsurface radar suffers from two typical problems, i.e., strong clutter from surface and severe wave attenuation in the underground. This paper presents a unique countermeasure to these problems using a polarimetric FM-CW radar and an equivalent sensitivity time control (STC) technique. The authors apply the polarimetric filtering principle to suppress surface clutter either in the Co-pol channel or in the X-pol channel of synthetic aperture radar, yielding to polarimetric enhanced target image. This technique works when the surface clutter and target have different polarization properties. Moreover, they use an equivalent STC technique specially suited for FM-CW radar for a deep object sounding to compensate wave attenuation within the ground. These techniques contribute to a significant improvement of the radar performance and the detection image contrast, although the detection of the target is in general a much more complicated topic. The field experiments were carried out to show the usefulness of the method. Some detection results are presented 相似文献
11.
Random surface error effects on offset cylindrical reflector antennas 总被引:12,自引:0,他引:12
The focus of this paper is to characterize the average power pattern of an offset cylindrical parabolic reflector antenna subject to random surface errors. A novel computational method is developed for studying the random surface error effects on the boresight gain loss and the sidelobe levels of the average power pattern. The particular antenna dimensions used for this study are similar to the specifications for the second generation precipitation radar (PR-2) mission. In keeping with the requirements in the PR-2 mission, both the Ku and Ka frequency bands are considered. Random surface error effects are also studied for different edge taper levels. In addition to analysis of a reflector with uniform random surface errors, a nonuniform surface error case is presented in this study. This is an important consideration for evaluating the suitability of large deployable membrane reflector antennas for the PR-2 mission. 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1966,54(9):1171-1183
Metal shields (or fences) are useful in reducing the ground clutter received by a radar. The design of a clutter shield for an L-band monopulse radar employing a 60-ft parabolic reflector with Cassegrainian geometry is verified by scale-model measurements at Ka -band. It is shown that a 100-ft fence, at a distance 500 ft from the radar, will give a nominal one-way clutter reduction of 20 dB. Tracking is expected to be virtually unaffected down to about 7.8° in elevation, but the low limit on useful performance is about 4.8°. More than 10 dB additional clutter reduction can be achieved by cutting rectangular slots in the top edge of the fence. However, polarization dependence and antenna geometry yield an average clutter suppression of 5 dB. In addition, the slots as other periodic structures are subject to "grating lobes." These place a restriction on the fence geometry. This is investigated experimentally on the scale model and explained by a mathematical analysis. A nonperiodic edge treatment is expected to be free of this troublesome effect. 相似文献
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Schroder C.T. Scott W.R. Jr. Larson G.D. 《Geoscience and Remote Sensing, IEEE Transactions on》2002,40(6):1405-1415
A three-dimensional (3-D) finite-difference model for elastic waves in the ground has been developed and implemented. The model has been created to supplement the development of a sensor that uses elastic waves to detect buried land mines. The model is used to investigate the propagation characteristics of elastic waves in the ground and to explore the interaction of elastic waves with buried land mines. When elastic waves interact with a buried mine, a strong resonance occurs at the mine location. The resonance can be used to enhance the mine's signature and to distinguish the mine from clutter. Results presented in this paper explain the features of elastic wave propagation in the ground and show the interaction of elastic waves with both an anti-personnel mine and an anti-tank mine. 相似文献
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强海杂波与海面目标的复杂特性使得海面目标回波微弱,有效的海杂波抑制和稳健快速的目标检测是雷达对海上目标探测需考虑的重要因素。然而,现有的海面目标检测算法对于复杂环境下的目标检测性能有限,环境和目标特性适应性差。该文设计了一种杂波抑制和目标检测融合网络(INet),通过层归一化-传递和连接方法提取关键目标特征,采用注意力网络抑制杂波和增强目标,构建跨阶段局部残差网络保证检测网络的轻量化和准确性。基于导航雷达在多种观测条件下采集的回波数据,构建了海面目标雷达图像数据集;通过模型的预训练和平面位置显示器(PPI)图像的帧间积累对INet进行了优化,得到了Optimized INet(O-INet)模型。经过多种天气条件下实测数据测试和验证,并与YOLOv3, YOLOv4,双参数CFAR和二维CA-CFAR对比后证明,所提方法在提高检测概率、降低虚警率和复杂条件下的强泛化能力有显著优势。 相似文献
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Chi-Chih Chen Kishore Rama Rao Lee R. 《Antennas and Propagation, IEEE Transactions on》2003,51(3):371-377
A new ultrawide-bandwidth dielectric-rod antenna is presented with its application in detecting shallow targets, such as antipersonnel (AP) mines. The lowest hybrid mode is launched and guided along a circular-dielectric waveguide. The end of the waveguide is tapered to a point where electromagnetic waves are radiated out with field behavior similar to that radiated from a Hertzian dipole in the forward direction. The low antenna clutter and weak antenna-ground interaction are two unique features. Its near-field radiation properties are investigated by directly probing the fields and by numerical simulation with a three-dimensional finite-difference time-domain technique. Both measurement and numerical simulation results are presented for the detection of buried AP mines using a prototype dielectric-rod antenna operated at a frequency range from 1 to 6 GHz. 相似文献
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Detection of surface targets in sea clutter by shipborne radar 总被引:1,自引:0,他引:1
Doppler techniques do not aid detection by shipborne radar of small (drifting) surface targets in sea clutter, and such targets have no velocity spectrum distinguishable from that of the clutter. However, clutter decorrelation by rapid antenna scan, followed by camera or direct-view storage-tube integration, can give impressive gains in target/clutter visibility. With relative-motion displays, own ship's motion severely limits possible integration time by shifting the effective spot area of integration as the target is approached; this is neatly avoided by using a `true-motion? display. Further gains may be possible (at least for hovercraft radar) by using an antenna with a vertical difference pattern in which the null is laid on the sea surface as a fence. 相似文献
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探地雷达是地雷探测的有效技术之一,如何尽可能滤除雷达接收信号中的杂波成分而又不失目标信息是完成目标检测的关键。为增强目标信息,提高信噪比,提出将主成分分析子空间投影和基于RLS自适应滤波技术相结合的方法,通过VUB实测数据进行实验,结果证明了该方法的有效性。 相似文献
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频率步进雷达及其在小目标检测中的应用 总被引:7,自引:4,他引:3
在强杂波环境下检测一类重要小目标(如巡航导弹,反舰掠海导弹,隐身飞机)是现代雷达面临的一个最具有挑战性的课题。频率步进雷达,由于其高距离分辨能力及独特的波形和处理,正在用来解决强杂波中小目标的检测问题。文中首先介绍了频率步进宽带高距离分辨雷达的原理和技术,然后讨论了应用频率步进雷达解决强杂波中运动小目标的无杂波区检测和无折叠杂波检测问题。 相似文献