基于小波域KL变换的探地雷达信号处理

探地雷达目标回波信号通常会受到串扰(或直达波)、随机噪声等的干扰,致使目标信号难以分辨。利用小波分析的时频局部化特性和多道探地雷达记录中直达波、目标回波信号以及随机噪声等的不同相关性,对探地雷达记录进行小波分解,得到多频段的小波剖面,再对不同频段的小波剖面做KL变换,实现了串扰抑制。通过实验数据和现场实测数据验证了该方法的有效性。     

去除探地雷达信号直达波的小波变换方法

简单介绍了二维连续小波变换的基本理论，详细分析了二维连续有向小波变换去除直达波的基本原理，对比了二维Cauchy小波及Morlet小波函数的性质，进而讨论了实际工程应用中小波函数的选择问题。通过实际工程探地雷达资料检验了该方法的有效性。     

曙光雷达数据处理软件系统

针对岩土工程探测对象的隐蔽性与复杂性,开发了曙光雷达数据处理软件系统,实现了不同类型雷达数据的共享数据处理、分形处理、偏移、联合反演、小波变换等功能;现场验证及试用结果表明,该软件系统可以改善地下目的物探测的分辨率和真实度,可为岩土工程施工提供较准确的地下障碍物资料。     

探地雷达在铁路隧道检测中的应用

基于铁路隧道衬砌质量检测项目,结合探地雷达检测过程中发现的一些问题,列举了不同地质情况下,隧道衬砌检测、衬砌背后回填密实程度检测、钢筋检测、钢架检测的典型雷达图像特征.     

Application of ground penetrating radar in mapping and monitoring landfill sites

The internal structure and the integrity of the containment walls are aspects of landfill site management that need to be continuously monitored. Monitoring currently involves construction of boreholes and chemical analyses of surface samples which are time-consuming and expensive. The applicability of ground penetrating radar (GPR) as an aid to monitoring these processes has been investigated. GPR surveys have successfully resolved the shallow depth soil and geological structure, identified the structure and history of the waste input, defined the water table in three dimensions and identified leachout breakout points in the impermeable lining of the landfill edges. Integration of the results of GPR surveys with data from surface surveys and boreholes could provide landfill operators, environmental agencies and commercial companies with a cost-effective monitoring methodology and a mechanism for enhancing contaminant migration modelling.     

探地雷达小波的构造及在提高雷达信号分辨率中的应用

从理论上详细分析了探地雷达子波的形成机理,提出了一种构造探地雷达小波函数的方法。与Cauchy小波及Morlet小波相比,以这种小波作为基本小波,应用于探地雷达实际资料处理中,在提高探地雷达剖面分辨率的同时,还能保持较高的信噪比     

瞬时属性估计器在探地雷达数据处理中的应用

为了提高浅层埋藏目标识别的瞬时物理属性的精度,根据极平坦频率特性有限脉冲相应滤波器的思想,首次提出用它作为微分器和延时器组成解析信号瞬时属性估计器（FIFM）,对探地雷达信号的瞬时属性进行提取。结果表明,瞬时属性剖面的分辨率得到了明显的提高;采用瞬时属性估计器进行探地雷达信号瞬时参数的研究是一种非常有效的方法,可用于公路、桥梁、隧道等结构物的无损检测数据分析。     

探地雷达技术在煤矿采空区探测中的应用

不明采空区对煤矿的安全生产构成潜在危害,而人工地震勘探对埋深较浅的采空区存在盲区。采用RAMAC/GPR探地雷达仪配备的超强地面耦合天线(RTA50MHz)探测采空区。由于煤层及采空区相对雷达探测的有效范围较深,综合考虑探地雷达的分辨率与探测深度的关系,选用合适的雷达参数和探测模式进行数据采集,并采用了VC++开发了三维系统进行了补充解释,实现了探测目标体的准确定位,取得较好的探测效果。     

Enhancing understanding of breakdown and collapse in the Yorkshire Dales using ground penetrating radar on cave sediments

Historical evidence shows block breakdown and collapse are actively occurring in large fault aligned caverns in the Yorkshire Dales karst. Deployment of ground penetrating radar at two such sites has provided detailed images of the sedimentary sequences below the present day cavern floor but no large blocks are imaged within the sediments. Solutional processes must be removing limestone from the sediment to allow continued cavern growth. Possible mechanisms to account for the lack of large blocks within the sediment fill are discussed.     

Collapse hazard assessment in evaporitic materials from ground penetrating radar: a case study

Evaporitic materials have been studied by means of ground penetrating radar (GPR) in order to evaluate the collapse hazard. The obtained 200 MHz GPR profiles show a low signal-noise ratio over the first 3 m depth, where well-defined and continuous reflectors can be observed. Between 3 and 4.5 m depth, the signal to noise ratio decreases due to attenuation of the electromagnetic (EM) waves. As a result, reflectors located deeper than 3 m become more discontinuous and poorly defined. GPR profiles show trails of continuous and subhorizontal reflectors, with a slightly undulated and irregular geometry. Although some of these reflectors laterally vanish or seem to disappear, sudden interruptions or hyperbolic reflections that could be originated by the occurrence of cavities have not been detected. These reflectors have been interpreted as corresponding to several evaporitic layers (gypsum) that constitute the main lithology in the area. Clear interruptions of reflectors have only been observed in some GPR profiles, and they could be attributed to small (1–2 m long) subvertical faults, with only a few centimetres offset. These faults may be generated by the accommodation of the evaporitic layers to local collapses affecting deeper materials.     

探地雷达探测地下管线机理研究及实例分析

探地雷达是一种适应快速、准确探测地下障碍物而迅速发展的新型电磁仪器。探讨了探地雷达探测地下管线的机理,得出了走时曲线方程,并通过对探测实例详细地分析亦探讨了复杂条件下探地雷达资料采集和图像解释的方法,介绍了一维滤波、偏移回归、时深转换等数据处理方法和经验,验证了该方法的可行性,表明该技术具有良好地应用前景。     

一种用于混凝土结构探测的探地雷达天线阵列的设计

基于脉冲体制探地雷达天线原理,针对混凝土结构探测的需求,以变形领结天线为基础,设计了一种双极化、多天线的探地雷达天线阵列,该天线阵列具有0.75~2.25 GHz 的频带宽度,且方向性良好。该天线阵列不仅可以提高雷达系统的探测深度,也提高了雷达的探测效率。设计的天线阵列已成功应用于成像探地雷达项目中,对工程质量检测具有重要意义,为探地雷达三维成像设备的进一步开发提供了强有力的技术支撑。     

堤防动物洞穴的探地雷达探测研究

通过探地雷达对淮沭河大堤獾洞隐患的探测,分析了獾洞的结构特征,给出了獾洞的典型雷达图像特征,推断了测区内獾洞穴道的位置、深度和走向,为堤防獾洞隐患治理提供了资料。探测结果表明,探地雷达设备轻便,对场地要求低,易于在任意方向加密探测,对浅层地下洞穴的探测非常有效。     

Experimental study on soil pollution analysis around tailings using ground penetrating radar

Pollution caused by tailings has become a serious environmental problem in China. An attempt was made to establish the ground penetrating radar （GPR） as a quick and non-destructive method for soil pollution analysis. Some physical models were established of contaminated soils from the tailing area. A series of indoor GPR experiments were conducted with 1 GHz antenna. The interface of contaminated area and uncontaminated area is characterized as a saltation zone in the radar image. The results of experiments show a clear correlation between the GPR data and the pollution intensity of soil. Based on all experimental data, the relation of velocity of electromagnetic wave propagation and pollution intensity was induced by using artificial neural network （ANN）. The results obtained indicate that GPR can provide high-resolution estimates of soil pollution variations around tailings as a function of depth as well as space and time.     

探地雷达在公路隧道衬砌检测中的应用

分析总结了隧道衬砌存在的常见问题及缺陷在雷达图像中的显现特征,并将探测结果与实际地质概况进行对比分析。结果表明,探地雷达能够对隧道衬砌实施连续扫描,获得形象直观的探测图像,利用探地雷达检测公路隧道衬砌,具有无损、快速、广泛、精确等优点。     

X3M探地雷达在城市地下管线探查中的应用

论文介绍了X3M探地雷达在地下管线探查的应用,对一些典型的探测图像进行了说明,并对其工作方法提出了一些建议。     

地质雷达电磁干扰分析及在隧洞岩溶探测中的应用

将地质雷达用于千岛湖配水工程某隧洞岩溶探测,分析了倾斜状电磁干扰异常与溶洞雷达异常差异,通过雷达剖面及疑似异常区单道时间-频率谱的分析,推断了隧底岩溶的性质及空间分布特征,含水溶洞在雷达剖面反映为同相轴错断,强振幅及能量高衰减的特性,高频干扰波振幅幅值较异常区小且能量不满足随时间推移逐渐衰减的规律,雷达成果为隧洞安全施工提供了准确的参考。      

GPＲ 探测电力工程地埋管线的技术方法

在电力工程地埋管线探测中,GPＲ 是一种行之有效的方法。为提高管线探测的精度,降低工程施工风险,笔者从探地雷达野外数据采集开始,详细探讨了探地雷达应用于管线探测时的数据采集方法 ( 包括测线的布设、干扰因素的避让等) 和室内后续数据处理的策略。针对管线探测这一目标,采用预测反褶积技术压制多次波和非线性颜色分级的剖面显示方式是提高数据解释精度的关键,并结合电力隧道地下管线探测实例验证了本文所提方法的有效性。     

基于瞬时相位余弦的探地雷达多层路面自动检测

层位特征是探地雷达路面检测的重要信息,而目前基于人工或相关算法的层位拾取方法存在主观性强、工作量大和每次仅能追踪一个层位等问题。为此,提出了一种基于探地雷达瞬时相位余弦的多层位自动追踪方法。首先,通过复信号分析获取了雷达数据的瞬时相位余弦;其次,利用子波余弦矩阵数据进行相似度分析后再计算其瞬时相位余弦,增强相位数据同相轴的横向连续性;然后,获取相位数据的空间位置、振幅和极性信息,并在信号幅值和同相轴特征等一系列约束条件下自动追踪横向连续的层位线;最后,通过比较深度方向相邻层位线上振幅的均方根平方值来确定层位数据及其极性,并通过设置层位线阈值和振幅阈值来提取强振幅连续的层位线数据。数值模拟和现场案例分析验证了本文方法的有效性和适应性。     

基于背景矩阵减法的探地雷达杂波信号抑制方法研究

探地雷达是探测浅层地下目标并对其空间分布进行成像的重要地球物理方法之一,但在实测雷达剖面中,目标反射信号不可避免地会受到直达波和地面反射波等杂波信号的干扰.为了提高探地雷达数据解译的可靠性和准确性,需要对杂波进行抑制或去除.提出一种背景矩阵减法来抑制杂波信号,并通过两组仿真数据和两组实测数据示例与减平均道法、奇异分解法...