共查询到19条相似文献,搜索用时 187 毫秒
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无载频脉冲探地雷达性能分析及其FD—TD法数值模拟计算 总被引:1,自引:0,他引:1
探测深度和分辩率是探地雷达的两项重要指标。本文分别对无载频脉冲探地雷达的探测深度和分辩率进行了分析,指出了影响雷达探测深度和分辩率的因素,并利用2。5维时时有限差分方法对雷达的探测性能进行了数值模拟计算,给出了地下单体目标和多体目标的回波信号电平图,并将部分计算结果与实验测试结果进行了对比,二者具有好的一致性。 相似文献
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以不同情况下的地埋目标散射特性为前提,能够准确地从探地雷达图像中提取目标体的结构信息。使用CST仿真软件上的时域求解器构建频率范围在0.5~3.5 GHz的脉冲体制探地雷达系统的目标散射仿真模型,并对不同传播介质、不同目标体与不同埋藏深度的地埋目标散射特性进行电磁仿真模拟,预演了多种情况下探地雷达系统的探测过程。通过比较不同情况下探地模型的目标回波信号,得出结论:土壤含水会使地面反射增强,目标回波衰减不易识别;目标的尺寸改变对回波幅度有影响,对波形影响不大;当目标材质的电参数改变时,目标体回波波形变化明显;当目标与传播介质的电参数相差较大时,目标回波明显;随着目标埋深增加,目标体回波在时域上向后延迟,可以根据回波时间差计算目标体埋深。通过对仿真结果的分析证明该方法可靠有效,并且仿真过程简便,适用于不同情况下探地雷达的目标散射模拟。 相似文献
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为了更好地解译探地雷达(ground-penetrating radar,GPR)回波数据,建立了一种二维时域有限差分模型,用于模拟地下分层结构(混凝土层/粘土层)和多个埋藏目标(金属板/条、空洞、水/油管)的GPR探测.对于该模型,地下分层结构中的分界面设置为粗糙界面,采用电磁微分高斯脉冲作为GPR源,并用单轴完全匹配层介质对计算区域边界进行截断以模拟无界区域.通过数值计算得到了探地雷达B-scan扫描的回波仿真结果,并讨论了埋藏深度、几何形状、介电常数、电导率等对回波散射特性的影响,以及目标受其上方不同粗糙度的粗糙界面影响而产生的回波形态的改变.该结果中显示的各个回波的形态、方位、振幅强弱以及到达的时间均与模型中各个结构的外形、位置、媒质特性及埋藏深度相一致,验证了该计算模型的有效性. 相似文献
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Burnside W. Gilreath M. Kent B. Clerici G. 《Antennas and Propagation, IEEE Transactions on》1987,35(2):176-182
For many years, the compact range has successfully been used to design and evaluate many electromagnetic radiation and scattering systems. However, it has had limited use for large structures because of the large discrepancy between the reflector and target zone sizes. The limitation results from the large edge diffracted signal which emanates from the termination of the reflector. Previous attempts to solve this problem have involved using serrated edges to diffuse the diffracted field. While this reduces the edge diffracted field in the target zone, it is not eliminated. In addition, one has introduced many new corners which also diffract into the target zone. A curved edge modification is presented which reduces the edge diffraction by an order of magnitude or more and in the process does not create new mechanisms which perturb the plane wave in the target zone. Using this curved modification, one is able to design a compact range reflector whose target zone cross section approaches the size of the reflector parabolic surface. This makes the compact range ideal for scale model measurements since larger targets (antennas) can be measured. It also makes it more practical to consider systems which can measure full scale vehicles. 相似文献
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利用无损探测技术来获取地下目标的信息是当前研究的热点,探地雷达(GPR)作为一种重要的无损工具,已被广泛用于检测,定位和特征化地下目标。然而,从GPR成像中探测掩埋物体并评估其位置既费时又费力。因此,实现地下目标的自动化探测对实际应用是必要的。为此,该文在综合分析地下目标回波特征的基础上,讨论了使用GPR评估目标位置的可行性,并回顾了国内外学者在GPR成像中对双曲线特征自动化检测的研究进展。该文还在国内外典型实例剖析的基础上,总结并比较了目标检测的处理方法。最后指出,未来的研究应集中于开发新的深度学习检测框架,用以自动检测和估计真实场景中的地下特征。 相似文献
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伪随机序列编码脉冲信号在探地雷达中的应用研究 总被引:2,自引:0,他引:2
探测深度是探地雷达最为重要的指标之一,在一定分辨率情况下如何增加探测深度一直是国内外研究的热点问题。该文对伪随机序列编码脉冲信号在探地雷达中的应用进行了研究,分析了伪随机序列编码脉冲信号的特点以及探地雷达对发射信号的应用需求,介绍了一个采用m序列二相脉冲调制的探地雷达实验系统,给出了该系统的测试和实验结果并对实验结果进行了理论分析,实验结果与理论分析十分吻合。分析与实验结果表明:在同样条件下,伪随机序列编码脉冲探地雷达较传统的Impulse探地雷达可以实现更大的探测深度,可以满足考古、地质勘察等深层探测应用的需求。 相似文献
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Effective imaging of buried dielectric objects 总被引:1,自引:0,他引:1
Ultrawide-band CW radar have shown good potential for remote imaging of surface laid or shallow buried landmine-like objects. However when sensing fields near to the ground, a number of factors including direct antenna coupling, air/ground coupling, receiver noise floor, and effective dynamic range conspire to degrade or mask the scattered return, resulting in a loss of signal magnitude, range accuracy, and range resolution. The present paper addresses the latter problems using a near-field detection methodology and providing a thorough experimental and systems analysis of the signal-to-clutter issues. The method proves advantageous in sensing weak echoes in the vicinity of the sensor from objects of low dielectric contrast with their environment. To enhance image processing gains, an effective space frequency synthetic aperture technique applicable to the two-media problem is outlined. The algorithm is straightforward and robust enough to be implemented on compact GPR systems operating in real time. The remaining problem of object identification will not be addressed here. To demonstrate the utility of these combined techniques, field experiments, over different frequency bands, were conducted and their results are reported 相似文献
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FDTD分析探地雷达天线的辐射特性 总被引:4,自引:0,他引:4
探地雷达系统一般采用超宽带短脉冲信号,因而其天线系统必须具有较好的宽带性能。只有几种类型的宽带天线能够用于探地雷达系统中,如电阻加载的蝶形天线、TEM喇叭天线及其变形形式。本文将给出一种新型的探地雷达天线,该天线为置于镜像面上且具有离散指数电阻加载的单偶极子。文中将采用FDTD计算和分析该天线在自由空间和有耗媒质上方时的辐射特性。结果表明,通过选择一定的电阻加载形式,可使天线具有较好的辐射波形,从而能够满足实际探地雷达的需要。最后,通过地下目标散射场的理论结果和实验结果说明了本文所采用方法的正确性。 相似文献
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