Concrete inspection is a well-known use of GPR. The advent of modem GPR instruments combined with vastly increasing computing power and rapidly improving software permits more effective use of GPR. The impediment to wider use is now the ease-of-use of GPR technology for the average commercial user. The requirements for concrete inspection are many and varied. The most common is to clear areas prior to cutting and coring for the installation of utilities or renovations. The requirement is a quick means of knowing how to avoid critical elements such as posttension cables or embedded utilities. Structural applications address the integrity of the concrete itself such as the presence of voids/air pockets, chemical alteration, or cracking. Owing to the less well defined and site specific character of such features, GPR applicability is unpredictable and interpretation of results still depends on gaining experience with the specific site conditions. Intrusive investigation must augment GPR findings to draw definitive conclusions. The embedded object class of problems is readily tractable with GPR. In the last year we focused on development of a system which enables non-GPR specialists to image concrete. The system required integration of a GPR sensor with a positioning procedure and on site data processing in a single package. The output is depth slice maps that allow the operator to immediately select cutting and coring locations. Systematic ergonomic procedures to make operation easy for average concrete users represented a major challenge. In this paper we discuss the design considerations and present the final system embodiment. We use a number of data examples from real environments to illustrate the development.
{"title":"Application of GPR to map concrete to delineate embedded structural elements and defects","authors":"A. P. Annan, S. Cosway, T. DeSouza","doi":"10.1117/12.462215","DOIUrl":"https://doi.org/10.1117/12.462215","url":null,"abstract":"Concrete inspection is a well-known use of GPR. The advent of modem GPR instruments combined with vastly increasing computing power and rapidly improving software permits more effective use of GPR. The impediment to wider use is now the ease-of-use of GPR technology for the average commercial user. The requirements for concrete inspection are many and varied. The most common is to clear areas prior to cutting and coring for the installation of utilities or renovations. The requirement is a quick means of knowing how to avoid critical elements such as posttension cables or embedded utilities. Structural applications address the integrity of the concrete itself such as the presence of voids/air pockets, chemical alteration, or cracking. Owing to the less well defined and site specific character of such features, GPR applicability is unpredictable and interpretation of results still depends on gaining experience with the specific site conditions. Intrusive investigation must augment GPR findings to draw definitive conclusions. The embedded object class of problems is readily tractable with GPR. In the last year we focused on development of a system which enables non-GPR specialists to image concrete. The system required integration of a GPR sensor with a positioning procedure and on site data processing in a single package. The output is depth slice maps that allow the operator to immediately select cutting and coring locations. Systematic ergonomic procedures to make operation easy for average concrete users represented a major challenge. In this paper we discuss the design considerations and present the final system embodiment. We use a number of data examples from real environments to illustrate the development.","PeriodicalId":256772,"journal":{"name":"International Conference on Ground Penetrating Radar","volume":"195 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122023337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Pieraccini, G. Luzi, D. Mecatti, L. Noferini, C. Atzeni
In this paper a high-frequency large-bandwidth synthetic - aperture penetrating radar for inspecting masonry structures is described. A Continuous Wave Step Frequency (CW-SF) radar operating at 10 GHz centre frequency with 4 GHz bandwidth has been designed and built. The system is operated in a non-contact manner by mechanically moving the transmitting and receiving antennas in order to synthesize a N-dimensional aperture up to 3 m in length and 1 m in height. In spite of the fact that penetration depth decreases dramatically with increasing frequency, a penetration depth up to several tens of centimetres in masonry, that can be satisfactory in a number of applications, was observed. The high central frequency, making available very large bandwidths, provides high resolution images of the investigated structures. Laboratory tests in order to assess the performances of the system are reported.
{"title":"High-frequency penetrating radar for masonry investigation","authors":"M. Pieraccini, G. Luzi, D. Mecatti, L. Noferini, C. Atzeni","doi":"10.1117/12.462317","DOIUrl":"https://doi.org/10.1117/12.462317","url":null,"abstract":"In this paper a high-frequency large-bandwidth synthetic - aperture penetrating radar for inspecting masonry structures is described. A Continuous Wave Step Frequency (CW-SF) radar operating at 10 GHz centre frequency with 4 GHz bandwidth has been designed and built. The system is operated in a non-contact manner by mechanically moving the transmitting and receiving antennas in order to synthesize a N-dimensional aperture up to 3 m in length and 1 m in height. In spite of the fact that penetration depth decreases dramatically with increasing frequency, a penetration depth up to several tens of centimetres in masonry, that can be satisfactory in a number of applications, was observed. The high central frequency, making available very large bandwidths, provides high resolution images of the investigated structures. Laboratory tests in order to assess the performances of the system are reported.","PeriodicalId":256772,"journal":{"name":"International Conference on Ground Penetrating Radar","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125546521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the last century ice bodies have changed significantly worldwide in response to climatic changes, apparently enhanced during the last decades, presumably owing to anthropogenic influence. Shrinkage of glaciers in the northern latitudes has been extensively documented; however, the behavior of glaciers in tropical or inter-tropical latitudes has been difficult to document. In Mexico, small glaciers are present in the highest mountains: Citlaltdpetl (5675 m), Popocatepetl (5452 m) and Iztaccthuatl (5286 m), all of them volcanoes. The glaciers of Mexico offer important clues about climate change at this latitude. Current inventory and monitoring of Mexican glaciers includes determination of glaciated areas and volumes. A survey has been carried out using ground-penetrating radar in order to get a figure of thickness and a preliminary volumetric estimate of an ice body of IztaccIhuatl volcano named Ayoloco glacier. A radar profile 415 m in length was obtained at a mean altitude of 5000 m with an azimuth of 190°, in a relatively flat area known as La Panza on top of the mountain. 100 Mhz antennas were used in the reflection mode with a separation of 2.5 m and a step-size of 2.5 m. A common mid-point survey was performed comprising 12 stations, at 0.5 m steps, to determine the wave velocity propagation in the ice-rock mixture that constitutes the glacier. Results yield a value of 0. 17 m/ns, which is close to the reported value for ice of 0. 1 6 m/ns. We find a layered structure perturbed by faulting at various inclinations, and an interface between the glacier and the underlying rock along a concave surface, shallow at the profile's extremes. There appears to be a transition at 50 m depth, from brittle to ductile ice. Since Iztaccihuatl volcano has many craters near the summit, we infer that this profile reveals the shape of one of the craters, which has been filled by the glacier's ice and a mixture of rock fragments and volcanic debris. The estimated upper volume of the Ayoloco glacier is 10.04 x 106 m3; this figure will have to be revised when more, perpendicular GPR transects are performed.
在上个世纪，全世界的冰体因气候变化而发生了显著变化，在过去几十年中明显增强，可能是由于人为影响。北纬地区冰川的萎缩已被广泛记录;然而，冰川在热带或热带间纬度的行为一直难以记录。在墨西哥，在最高的山上有小冰川:Citlaltdpetl(5675米)，Popocatepetl(5452米)和Iztaccthuatl(5286米)，它们都是火山。墨西哥的冰川为这个纬度的气候变化提供了重要线索。目前对墨西哥冰川的清查和监测包括确定冰川面积和体积。利用探地雷达对伊兹塔奇瓦尔特火山的阿约洛科冰川冰体进行了厚度测量和初步体积估算。在平均海拔5000米，方位角190°的地方，在山顶一个被称为La Panza的相对平坦的地区，获得了长415米的雷达剖面图。反射模式采用100 Mhz天线，间隔2.5 m，步长2.5 m。进行了一个普通的中点调查，包括12个站点，以0.5米的台阶，以确定波速在构成冰川的冰-岩混合物中传播。结果产生一个值0。17 m/ns，这与报道的冰的0。1 6m /ns。我们发现了一个被不同倾斜度的断层扰动的层状结构，以及冰川和下伏岩石之间沿凹表面的界面，在剖面的极端处很浅。在50米深处似乎有一个从脆性冰到韧性冰的转变。由于Iztaccihuatl火山在山顶附近有许多陨石坑，我们推断这张剖面揭示了其中一个陨石坑的形状，这个陨石坑被冰川的冰、岩石碎片和火山碎片的混合物填满。估计阿约洛科冰川的上部体积为10.04 x 106立方米;当进行更多的垂直探地雷达横断面时，必须修改此图。
{"title":"Characterization of a tropical ice body on Iztaccihuatl volcano, Mexico","authors":"R. Álvarez, H. Delgado","doi":"10.1117/12.462267","DOIUrl":"https://doi.org/10.1117/12.462267","url":null,"abstract":"In the last century ice bodies have changed significantly worldwide in response to climatic changes, apparently enhanced during the last decades, presumably owing to anthropogenic influence. Shrinkage of glaciers in the northern latitudes has been extensively documented; however, the behavior of glaciers in tropical or inter-tropical latitudes has been difficult to document. In Mexico, small glaciers are present in the highest mountains: Citlaltdpetl (5675 m), Popocatepetl (5452 m) and Iztaccthuatl (5286 m), all of them volcanoes. The glaciers of Mexico offer important clues about climate change at this latitude. Current inventory and monitoring of Mexican glaciers includes determination of glaciated areas and volumes. A survey has been carried out using ground-penetrating radar in order to get a figure of thickness and a preliminary volumetric estimate of an ice body of IztaccIhuatl volcano named Ayoloco glacier. A radar profile 415 m in length was obtained at a mean altitude of 5000 m with an azimuth of 190°, in a relatively flat area known as La Panza on top of the mountain. 100 Mhz antennas were used in the reflection mode with a separation of 2.5 m and a step-size of 2.5 m. A common mid-point survey was performed comprising 12 stations, at 0.5 m steps, to determine the wave velocity propagation in the ice-rock mixture that constitutes the glacier. Results yield a value of 0. 17 m/ns, which is close to the reported value for ice of 0. 1 6 m/ns. We find a layered structure perturbed by faulting at various inclinations, and an interface between the glacier and the underlying rock along a concave surface, shallow at the profile's extremes. There appears to be a transition at 50 m depth, from brittle to ductile ice. Since Iztaccihuatl volcano has many craters near the summit, we infer that this profile reveals the shape of one of the craters, which has been filled by the glacier's ice and a mixture of rock fragments and volcanic debris. The estimated upper volume of the Ayoloco glacier is 10.04 x 106 m3; this figure will have to be revised when more, perpendicular GPR transects are performed.","PeriodicalId":256772,"journal":{"name":"International Conference on Ground Penetrating Radar","volume":"18 11","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114106828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT The GPR data acquisition software is arguably one of the most important components of a Ground Penetrating Radar system. This software needs to ensure the capture of reliable and repeatable data by a diverse user community. Yet, too many commercial and academic systems provide a single- user highly configurable interface for all applications. This paper describes the development of a configurable data acquisition and display application for use with ground penetrating radar. It is proposed that the standard GUI-based application that offers access to all controls and settings is distracting to many GPR end-users. It is therefore suggested that an application should present only the necessary controls to the end-user, and all other options should be inaccessible. This paper describes the development of such an application from a user requirements analysis to the design and implementation of an object-oriented, Java-based solution.
{"title":"Dynamically configurable GPR data acquisition and display application","authors":"A. Wallis, A. Langman, M. Inggs","doi":"10.1117/12.462295","DOIUrl":"https://doi.org/10.1117/12.462295","url":null,"abstract":"ABSTRACT The GPR data acquisition software is arguably one of the most important components of a Ground Penetrating Radar system. This software needs to ensure the capture of reliable and repeatable data by a diverse user community. Yet, too many commercial and academic systems provide a single- user highly configurable interface for all applications. This paper describes the development of a configurable data acquisition and display application for use with ground penetrating radar. It is proposed that the standard GUI-based application that offers access to all controls and settings is distracting to many GPR end-users. It is therefore suggested that an application should present only the necessary controls to the end-user, and all other options should be inaccessible. This paper describes the development of such an application from a user requirements analysis to the design and implementation of an object-oriented, Java-based solution.","PeriodicalId":256772,"journal":{"name":"International Conference on Ground Penetrating Radar","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130240348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A three-dimensional (3-D) georadar survey has been conducted across a 41.2 x 34.5m area with moderate topographic relief (dips: 4 - 16°) near Randa in southwestern Switzerland. For this survey, we employed a semiautomated acquisition system that combined a standard georadar unit with a self-tracking theodolite. This system recorded georadar data and coordinates simultaneously. Subsequently, an accurate topographic model of the acquisition surface was determined from the measured coordinates. With the aid of this topographic model, a provisional static correction for each georadar trace was determined. Application of the static corrections removed the most significant distortions of the major reflections and diffractions, which likely originated from the soil-rock interface and/or major fractures.
在瑞士西南部Randa附近的一个41.2 x 34.5m的区域进行了三维(3-D)地质雷达调查，该区域地形起伏适中(倾角:4 - 16°)。在这次调查中，我们采用了一种半自动采集系统，该系统将标准地质雷达单元与自跟踪经纬仪相结合。该系统同时记录地质雷达数据和坐标。随后，根据测量坐标确定采集面精确的地形模型。利用该地形模型，确定了每条地质雷达道的临时静校正量。静校正的应用消除了主要反射和衍射的最显著畸变，这些畸变可能源于土-岩界面和/或主要裂缝。
{"title":"3D georadar surveying in areas of moderate topographic relief","authors":"B. Heincke, T. Spillmann, H. Horstmeyer, A. Green","doi":"10.1117/12.462261","DOIUrl":"https://doi.org/10.1117/12.462261","url":null,"abstract":"A three-dimensional (3-D) georadar survey has been conducted across a 41.2 x 34.5m area with moderate topographic relief (dips: 4 - 16°) near Randa in southwestern Switzerland. For this survey, we employed a semiautomated acquisition system that combined a standard georadar unit with a self-tracking theodolite. This system recorded georadar data and coordinates simultaneously. Subsequently, an accurate topographic model of the acquisition surface was determined from the measured coordinates. With the aid of this topographic model, a provisional static correction for each georadar trace was determined. Application of the static corrections removed the most significant distortions of the major reflections and diffractions, which likely originated from the soil-rock interface and/or major fractures.","PeriodicalId":256772,"journal":{"name":"International Conference on Ground Penetrating Radar","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134240656","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
GPR surveys were conducted at two sites within the hillside town of Rennes-le-Château, France. The town is linked with many traditions and mysteries associated with the Templar movement and its treasure, including according to some documents, the possible location of the Holy Grail. Two locations were chosen for the initial project: the Tour Magdala and the Church of St. Mary Magdalen. The survey at the Tour Magdala was carried out to image any features that may be located beneath the tower floor or around its outer base. Results indicate the tower is built on the local bedrock with possible surface and subsurface disruptions in the local stratigraphy, while 3D cubes show a hyperbolic feature, which may indicate the possibility of a buried feature. The survey at the Church was carried out to image any features that may be located beneath the church floor. 2D and 3D images show a subsurface anomaly (hyperbolic feature) that extends along several parallel lines that may possibly indicate a burial crypt.
{"title":"Archaeological GPR investigation at Rennes-le-Chateau, France","authors":"H. Jol, R. J. DeChaine, R. Eisenman","doi":"10.1117/12.462201","DOIUrl":"https://doi.org/10.1117/12.462201","url":null,"abstract":"GPR surveys were conducted at two sites within the hillside town of Rennes-le-Château, France. The town is linked with many traditions and mysteries associated with the Templar movement and its treasure, including according to some documents, the possible location of the Holy Grail. Two locations were chosen for the initial project: the Tour Magdala and the Church of St. Mary Magdalen. The survey at the Tour Magdala was carried out to image any features that may be located beneath the tower floor or around its outer base. Results indicate the tower is built on the local bedrock with possible surface and subsurface disruptions in the local stratigraphy, while 3D cubes show a hyperbolic feature, which may indicate the possibility of a buried feature. The survey at the Church was carried out to image any features that may be located beneath the church floor. 2D and 3D images show a subsurface anomaly (hyperbolic feature) that extends along several parallel lines that may possibly indicate a burial crypt.","PeriodicalId":256772,"journal":{"name":"International Conference on Ground Penetrating Radar","volume":"243 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134145657","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optimal frequency bands for radar detection of buried anti-tank (AT) and anti-personal (AP) mines are substantiated. Mines geometry, permittivity of explosives and soils are taken into account. In that case we can obtain maximum number of parameters for identification of mines against a background of noises and false signals. Analysis of used antennas of ground penetrating radar (GPR) is completed. For improvement of mine detection probability we propose to use scanning antennas and focused scanning antennas.
{"title":"Novel method of plastic landmine radar detection","authors":"N. Chubinsky, A. Krampuls","doi":"10.1117/12.462312","DOIUrl":"https://doi.org/10.1117/12.462312","url":null,"abstract":"Optimal frequency bands for radar detection of buried anti-tank (AT) and anti-personal (AP) mines are substantiated. Mines geometry, permittivity of explosives and soils are taken into account. In that case we can obtain maximum number of parameters for identification of mines against a background of noises and false signals. Analysis of used antennas of ground penetrating radar (GPR) is completed. For improvement of mine detection probability we propose to use scanning antennas and focused scanning antennas.","PeriodicalId":256772,"journal":{"name":"International Conference on Ground Penetrating Radar","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121224510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Borehole ground penetrating radar (GPR) was used to measure the temporal and spatial variability of soil water content under uniform wetting and drying conditions. Zero Offset Gather (ZOG) surveys were conducted before and during the uniform infiltration and the subsequent drainage experiments using the PuLseEKKO 100 borehole system with 200 MHz antennas in horizontal access tubes. Time domain reflectometry (TDR) data were collected from 10 vertical probes installed at 0. 1 m increments from 0.1 to 1.0 m below the ground surface. The TDR data were used as standard measures of soil water content to compare with the GPR estimated water content. The electromagnetic wave velocity along the survey profile at about 1 .0 m below the ground surface was estimated using ZOG data by picking the arrival time of the first event. Volumetric water content was calculated using a standard empirical relationship between velocity and water content for each ZOG location. Measured higher soil water content zones are potentially preferential flow areas and were observed in consistent locations throughout both the wetting and drying experiments. The radius of influence of the borehole GPR measurements was about 0.5 m determined theoretically and by comparing GPR and TDR data.
{"title":"Temporal and spatial variation of soil water content measured by borehole GPR under irrigation and drainage","authors":"L. Galagedara, G. Parkin, J. Redman, A. Endres","doi":"10.1117/12.462253","DOIUrl":"https://doi.org/10.1117/12.462253","url":null,"abstract":"Borehole ground penetrating radar (GPR) was used to measure the temporal and spatial variability of soil water content under uniform wetting and drying conditions. Zero Offset Gather (ZOG) surveys were conducted before and during the uniform infiltration and the subsequent drainage experiments using the PuLseEKKO 100 borehole system with 200 MHz antennas in horizontal access tubes. Time domain reflectometry (TDR) data were collected from 10 vertical probes installed at 0. 1 m increments from 0.1 to 1.0 m below the ground surface. The TDR data were used as standard measures of soil water content to compare with the GPR estimated water content. The electromagnetic wave velocity along the survey profile at about 1 .0 m below the ground surface was estimated using ZOG data by picking the arrival time of the first event. Volumetric water content was calculated using a standard empirical relationship between velocity and water content for each ZOG location. Measured higher soil water content zones are potentially preferential flow areas and were observed in consistent locations throughout both the wetting and drying experiments. The radius of influence of the borehole GPR measurements was about 0.5 m determined theoretically and by comparing GPR and TDR data.","PeriodicalId":256772,"journal":{"name":"International Conference on Ground Penetrating Radar","volume":"45 16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124473832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To understand better how a borehole antenna radiates radar waves into a formation, this phenomenon is simulated numerically using the finite-difference, time-domain method. The simulations are of two different antenna models that include features like a driving point fed by a coaxial cable, resistive loading of the antenna, and a water-filled borehole. For each model, traces are calculated in the far-field region, and then, from these traces, radiation patterns are calculated. The radiation patterns show that the amplitude of the radar wave is strongly affected by its frequency, its propagation direction, and the resistive loading of the antenna.
{"title":"Radiation pattern of a borehole radar antenna","authors":"K. Ellefsen, D. Wright","doi":"10.1117/12.462190","DOIUrl":"https://doi.org/10.1117/12.462190","url":null,"abstract":"To understand better how a borehole antenna radiates radar waves into a formation, this phenomenon is simulated numerically using the finite-difference, time-domain method. The simulations are of two different antenna models that include features like a driving point fed by a coaxial cable, resistive loading of the antenna, and a water-filled borehole. For each model, traces are calculated in the far-field region, and then, from these traces, radiation patterns are calculated. The radiation patterns show that the amplitude of the radar wave is strongly affected by its frequency, its propagation direction, and the resistive loading of the antenna.","PeriodicalId":256772,"journal":{"name":"International Conference on Ground Penetrating Radar","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129522002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Continuing improvements in computer technology have made 3-D imaging a standard GPR interpretation technique. The most common data collection methodology for 3-D imaging involves collection of data along parallel profile lines. The data are then often migrated and concatenated into a 3-D file. A 3-D image generated from the file is manipulated to detect linear and finite-size targets. The detection of linear and finite-size targets can be enhanced by creating images generated from data collected along orthogonal profile lines. The fact that the minimum angle formed between the long axis of a linear target and one of the orthogonal profile lines is 45 degrees enhances the detection of a linear target because in at least one profile line direction the reflection from the linear target will form the familiar hyperbola and a series of hyperbolas concatenated from parallel profile lines are readily observed in the 3-D image. Perhaps the most beneficial aspect of using bi-directional data is the ability to perform spatial filtering operators to improve detection of linear targets. Background removal filters applied to parallel profile line data will generally erase reflections from pipes or rebar that trend parallel to the direction of the profile lines. Comparisons of the data visualization capabilities between one-direction and orthogonal profile line data collected on reinforced concrete and on a buried pipe test site clearly show the advantages of imaging using orthogonal profile line data on both small and large scales.
{"title":"Enhanced target imaging in 3D using GPR data from orthogonal profile lines","authors":"R. Roberts, D. Cist","doi":"10.1117/12.462227","DOIUrl":"https://doi.org/10.1117/12.462227","url":null,"abstract":"Continuing improvements in computer technology have made 3-D imaging a standard GPR interpretation technique. The most common data collection methodology for 3-D imaging involves collection of data along parallel profile lines. The data are then often migrated and concatenated into a 3-D file. A 3-D image generated from the file is manipulated to detect linear and finite-size targets. The detection of linear and finite-size targets can be enhanced by creating images generated from data collected along orthogonal profile lines. The fact that the minimum angle formed between the long axis of a linear target and one of the orthogonal profile lines is 45 degrees enhances the detection of a linear target because in at least one profile line direction the reflection from the linear target will form the familiar hyperbola and a series of hyperbolas concatenated from parallel profile lines are readily observed in the 3-D image. Perhaps the most beneficial aspect of using bi-directional data is the ability to perform spatial filtering operators to improve detection of linear targets. Background removal filters applied to parallel profile line data will generally erase reflections from pipes or rebar that trend parallel to the direction of the profile lines. Comparisons of the data visualization capabilities between one-direction and orthogonal profile line data collected on reinforced concrete and on a buried pipe test site clearly show the advantages of imaging using orthogonal profile line data on both small and large scales.","PeriodicalId":256772,"journal":{"name":"International Conference on Ground Penetrating Radar","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121182891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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