Phased array radar systems employ multiple antennas to create a radar beam that can be steered electronically. By manipulating the relative phase values of feeding signals among different antennas, the effective radiation pattern of the array can be synthesized to enhance the main lobe in a desired direction while suppressing the undesired side lobes in other directions. Hence the radar scanning angles can be electronically controlled without employing the bulky mechanical gimbal structure, which can significantly reduce radar system size, weight and power consumption. In recent years, phased array technologies have received great attentions and are explored in developing many new applications, such as smart communication systems, military radars, vehicular radar, etc. Most of these systems are narrow band systems, where the phase delays are realized with narrow band phase shifter circuits. For the impulse ground penetrating radar however, its operating frequency spans an ultrawide bandwidth. Therefore the traditional phase shifters are not applicable due to their narrow band nature. To resolve the issue, in this study, a true time delay approach is explored which can precisely control time delays for the feeding pulse signals among different antennas in the array. In the design, an on chip programmable delay generator is being developed using Global Foundry 0.18 µm 7 HV high voltage CMOS process. The time delay control is realized by designing a programmable phase locked loop (PLL) circuit which can generate true time delays ranging from 100 ps (picoseconds) to 500 ps with the step size of 25 ps. The PLL oscillator's frequency is programmable from 100MHz to 500MHz through two reconfigurable frequency dividers in the feedback loop. As a result, the antenna beam angle can be synthesized to change from 9.59° to 56.4° with a step of 2.75°, and the 3dB beamwidth is 10°. The power consumption of the time delay circuit is very low, where the supply voltage is 1.8V and the average current is as low as 472uA.

The Charity Hospital Cemetery in New Orleans, Louisiana, was used as a potter's field for over 150 years. When Charity Hospital considered selling a portion of the property ground penetrating radar (GPR) and thermal infrared (TIR) data were collected in the cemetery to locate unmarked graves. The TIR data could not be used because the expert died before compiling the TIR data. Therefore, the GPR data was the sole source of subsurface information. GPR anomalies were used to excavate 3 areas where bones and hospital supplies were subsequently found, unfortunately very limited analyses were possible on the analog GPR data. The study presented here involved digitizing data and conducting a more thorough analysis of map patterns to determine whether GPR data could be used reliably to locate burials in the cemetery. The study's result indicates that GPR is a reliable source for burial detection and other anomalies in the subsurface.

Peat soils are known to be a significant source of atmospheric greenhouse gasses. However, the releases of methane and carbon dioxide gasses from peat soils are currently not well understood, particularly since the timing of the releases are poorly constrained. Furthermore, most research work performed on peatlands has been focused on temperate to sub-arctic peatlands, while recent works have suggested that gas production rates from low-latitude peat soils are higher than those from colder climates. The purpose of the work proposed here is to introduce an autonomous Ground Penetrating Radar (GPR) method for investigating the timing of gas releases from peat soils at the lab scale utilizing samples originating from Maine and the Florida Everglades, and at the field scale in a Maine peatland. Geophysical data are supported by direct gas flux measurements using the flux chamber method enhanced by timelapse photography, and terrestrial LiDAR (TLS) monitoring surface deformation. / by William J. Wright. / Thesis (M.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

Ground penetrating radar (GPR) technology has existed for many decades, but it has only been in the last 20 to 30 years that it has undergone great development for use in near surface ground investigations. The early 1980's saw the first major developments in the application of GPR for pavements (i.e. engineered structures designed to carry traffic loads), and it is now an established investigation technique, with generic information included in several national standard guidance documents. Analysis of GPR data can provide information on layer depths, material condition, moisture, voiding, reinforcement and location of other features. Assessing the condition of pavements, in order to plan subsequent maintenance, is essential to allow the efficient long-term functioning of the structure and GPR has enhanced and improved the range and certainty of information that can be obtained from pavement investigations. Despite the recent establishment of the technique in pavement investigation, the current situation is one in which GPR is used routinely for pavement projects in only a minority of countries, and the specialist nature of the technique and the sometimes variable results that are obtained can mean that there is both a lack of appreciation and a lack of awareness of the potential information that GPR can provide. The fact that GPR is still a developing technique, and that many aspects of its use are specialised in their nature, means that there are also several technical aspects of GPR pavement investigations which have not been fully researched, and knowledge of the response of GPR to some material conditions has not been fully established. The overall aim of this EngD research project was to provide improved pavement investigation capabilities by enhancing the methodologies and procedures used to obtain information from GPR. Several discrete research topics were addressed through various research methods including a literature review, fieldwork investigations, experimental laboratory investigations and a review of previously collected data. The findings of the research allowed conclusions and recommendations to be made regarding improved fieldwork methodologies, enhancing information and determining material condition from previously collected GPR data, assessing the effect of pavement temperature and moisture condition on GPR data and also on managing errors and uncertainty in GPR data. During the EngD project, a number of documents and presentations have been made to publicise the findings both within the EngD sponsoring company (Jacobs) and externally, and an in-house GPR capability has been established within Jacobs as a direct result of the EngD project.

Concrete structures are susceptible to deterioration over time and it is vital to continually assess concrete structures to maintain the structural integrity and prolong the service life. In recent years there has been an increased interest in non-destructive testing of concrete, i.e. assessing the state of the concrete without causing any damage to the structure in the process. There are many different techniques that falls under the term non-destructive testing and one of these that have gained prominence during the last few years is Georadar or ground penetrating radar, often shortened as GPR. GPR is a technique where microwaves are sent into the surface of the concrete by a device, the waves will reflect back to the device when encountering interfaces of areas with different electric properties. The waves are then received by the same device indicating the internal structure of the concrete. This makes the technique an excellent way to find reinforcement bars as the electric properties of concrete and metal strongly differ. In theory though, the technique should also be able to detect other internal differences in concrete, such as voids and corrosion areas but further research is still needed in these areas. This aim of this report is to evaluate ground penetrating radar as a non-destructive technique for assessment of concrete structures. In order to do this different tests has been conducted to evaluate the general performance and usability with a literature review introducing the science behind and what conclusions other researches has reached and using a testing methodology to reach the results. The tests can in a simple way be divided into two parts, first lab tests on a slab in a controlled setting where the internal structure was known, and then two shorter field trips in order to evaluate the performance properly insitu. The results were, to some extent, ambiguous. Although it was found that GPR is an excellent method for finding and locating near-surface reinforcement it was also concluded that the results could vary significantly depending on the location. In one of the field trips the performance of the GPR technique was compared to the performance of traditional cover meter and in this case the portability of the cover meter outperformed the somewhat clunky handling of the GPR. The concrete cover measurement using post-processing of the radar data gave a rough estimate, but once again evaluation still relied on the insitu conditions and the estimate were sometimes questionable. Finding reinforcement below the first layer yielded differing results and it was concluded that further tests were needed to fully evaluate the capabilities of the technique in this regard. The conclusions of the thesis was that although the tests show some potential for the method the results expected from GPR would strongly depend on suitability of the project and experience of the user. One important limiting factor was the availability of devices. For the current project only one specific device was used, it was theorized that another GPR device could get better results depending on the purpose. Furthermore, the lack of experience was also considered to be a limiting factor that might have had an effect on the results. For future research more tests on lower reinforcement and tests on detection of deterioration were suggested. Comparative studies with other similar non-destructive techniques were also considered to be an area of possible interest.

O Pantanal é uma área mundialmente conhecida por ser uma das maiores planícies com alagamentos sazonais do mundo. Do ponto de vista de seus sistemas deposicionais, é uma área importante na caracterização de sistemas fluviais distributivos, característicos de áreas subsidentes e com grande relevância na interpretação do registro estratigráfico de sistemas fluviais em bacias sedimentares. Entretanto, os aspectos temporais da evolução dos sistemas fluviais do Pantanal são ainda pouco investigados, sendo ainda mais escassos os estudos com abordagem de investigações de sua subsuperfície. Como forma de contribuir para a compreensão da evolução temporal dos sistemas fluviais na região, o presente estudo apresenta os resultados de levantamentos de Radar de Penetração do Solo (GPR - Ground Penetrating Radar) e interpretação de radar fácies no Megaleque do Rio Taquari, no lobo meandrante do rio de mesmo nome, no Pantanal. Como resultado, após o processamento das informações coletadas, foram selecionadas nove seções GPR representativas do sistema, nas quais foram identificadas três radar fácies. Através da interpretação destas, foi possível identificar geometrias deposicionais em profundidades distintas do padrão formado pelos sistemas atuais, interpretadas como um sistema entrelaçado possivelmente de maior vazão que o atual e que implicam em transformações no sistema fluvial do rio Taquari no Quaternário, possivelmente devido a mudanças climáticas. / The Pantanal is internationally recognized as one of the largest seasonally flooded areas in the world. From a depositional systems point of view, it is important in the characterization of distributive fluvial systems, typical of subsiding areas and bearing great relevance for the interpretation of the fluvial rock record preserved within sedimentary basins. Despite that, the temporal aspects of the evolution of the fluvial systems in Pantanal are still poorly investigated, and studies based on subsurface surveys are even more scarce. As a means to contribute for the understanding of the fluvial systems evolution in the region, this dissertation presents the results of Ground Penetrating Radar (GPR ) surveys and radar facies interpretation in the Taquari river megafan, specifically in the meandering lobe of the homonymous river in the Pantanal. After data processing, nine GPR sections representative of the system were selected, in which three radar facies were identified. Their interpretation lead to the identification of subsurface depositional geometries which are distinct from the modern day patterns, interpreted as a braided system possibly with greater discharge than the modern meandering river. This implies in changes in the Taquari fluvial system in the Quaternary, probably due to climate change.

O presente trabalho tem como objetivo a reconstrução da história evolutiva ao longo do Holoceno da planície costeira de cordões litorâneos estabelecidos sobre o vale fluvial do Rio Itabapoana/ES. A partir desse objetivo, foram realizadas as seguintes etapas metodológicas: Sensoriamento Remoto, Topografia, Geofísica e Geocronologia. Através da análise da imagem de satélite RapidEye, na composição colorida R5-G3-B1, foram discriminadas classes de cobertura vegetal. A relação entre a vegetação e o solo exposto proporcionou a identificação de três padrões distintos na planície costeira de cordões litorâneos. A obtenção de dados contínuos de altimetria através de um sistema global de navegação por satélite (GNSS), concentrado no caminhamento perpendicular à linha de costa, permitiu a elaboração e análise do perfil altimétrico dos cordões litorâneos, identificando-se três principais características: 1) nos primeiros 600 m tem-se um acréscimo na elevação; 2) em seguida, uma longa faixa “estável”, de pouca mudança na elevação; 3) por fim, o decréscimo da elevação nos últimos 500 m. Para caracterizar a arquitetura deposicional em subsuperfície dos cordões litorâneos, utilizou-se um Radar de Penetração no Solo (GPR) O registro obtido com GPR possibilitou a identificação de três padrões, representados pelas unidades retrogradacional e progradacional, onde o padrão de empilhamento compõe uma sequência de barreira regressiva ou progradante. Para a obtenção de uma relação cronoestratigráfica, seis amostras de sedimentos da fração arenosa de deposição eólica foram coletadas para a obtenção de idades absolutas a partir de Luminescência Opticamente Estimulada (LOE). Os cordões datados apresentaram idades holocênicas, com idades inferiores a 5.261 ± 396 anos. A integração dos resultados obtidos através dos métodos aplicados permitiu o reconhecimento de três padrões que levaram à interpretação de três fases decorrentes das variações do nível relativo do mar e do aporte sedimentar na evolução da planície. Essas fases representam os períodos de transgressão, regressão normal e regressão forçada. / The aim of this study is the reconstruction of the evolutionary history along the Holocene of the of beach ridges coastal plain established on the fluvial valley of Itabapoana River/ES. From this objective, the following methodological steps were performed: Remote Sensing, Topography, Geophysics and Geochronology. Through the analysis of the RapidEye satellite image, in the color composition R5-G3-B1, classes of vegetal cover were discriminated. The relationship between vegetation and exposed soil provided the identification of three distinct patterns of the beach ridges coastal plain. Obtaining continuous data of altimetry with a GNSS system, concentrated in the path perpendicular to the coastline, allowed the elaboration and analysis of the altimetric profile of the beach ridges. It was identified three main characteristics: 1) in the first 600 m there is an increase in elevation; 2) then along “stable” stretch, with little change in elevation; 3) lastly, the decrease of the elevation in the last 500 m. A Ground Penetrating Radar (GPR) was used to characterize the depositional architecture in the subsurface of the beach ridges The GPR record allowed the identification of three patterns, represented by the retrogradational and progradational units, in which the stacking pattern consists of a regressive or progradational barrier sequence. Six sediment samples of the sandy fraction of wind deposition were collected to obtain absolute ages from Optically Stimulated Luminescence (OSL). The dated ridges presented Holocene ages, with ages lower than 5,261 ± 396 years. The integration of the results obtained allowed the recognition of three patterns that led to the interpretation of three phases due to the variations of the relative sea level and the sedimentary budget in the evolution of the plain. These phases represent periods of transgression, normal regression and forced regression.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Esta pesquisa investigou a formação de depósitos arenosos localizados na planície costeira da Baixada de Sepetiba, em Itaguaí, estado do Rio de Janeiro. A deposição sedimentar e a evolução desta área, na Baixada de Sepetiba tem sido estudada nas três últimas décadas, principalmente, porque é um ambiente de depósitos arenosos antigo de idade Holocênica a Pleistocênica que corresponde a uma linha de praia, originada com eventos transgressivos e/ou regressivos que tiveram seu ápice durante o Quaternário. A metodologia de Radar de Penetração no Solo (GPR) é usada, principalmente nos casos de trabalho em que se estuda um ambiente costeiro arenoso. Este campo da Geofísica tem sido usado para examinar características, tais como: a espessura de depósitos arenosos, a profundidade de um aqüífero, a detecção de uma rocha ou um aqüífero, e determina a direção de progradação. Esta pesquisa usa técnicas de radar de penetração no solo (GPR) para analisar as estruturas, em subsuperfície desde que o ambiente estudado seja definido como linha de costa, as margens de uma lagoa mixohalina, chamada Baía de Sepetiba. Neste trabalho realizamos um total de 11 perfis, que foram processados pelo software ReflexWin. Durante o processamento do dado aplicamos alguns filtros, tais como: subtract-mean (dewow), bandpassfrequency e ganhos. E as melhores imagens dos perfis foram realizadas usando-se uma antena de 200 MHz (canal 1) e outra antena de 80 MHz. Neste caso, obtivemos imagens de alta resolução a uma profundidade de até 25 metros. / This research investigated the formation of sandstones located in the coastal plain region of Sepetiba, in Itaguaí, Rio de Janeiro State. The deposition sedimentary and the evolution of the coastal plain Sepetiba has been studied in the last three decades, mainly because it is an ancient environment of sandy deposits formed during the Holocene. In addition, diverse authors define the sediments as deposited at beaches originated with transgressive and/or regressive that peaked during the Quaternary. The methodology of Ground Penetrating Radar (GPR) was here used to study the coastal sandy environment. This geophysical technique has been used to examine characteristics such as: thickness of the sand deposits, the detection of the bedrock and to determinate the direction of progradation. This research also used the technique of ground penetrating radar to analyze the structures in the subsurface since the environment studied can be defined as the shoreline, the margins of lagoon, called Sepetiba Bay. In this work we realized a total of eleven (11) profiles, which have been processed with the software Reflex win. During data processing apply some filters, such as: subtract mean (dewow), bandpassfrequency and gains. And the much better images of radargramas have been realized using a 200 MHz antenna (channel 1) and an antenna 80 MHz In this case, obtained images of radargramas with high resolution to 25 meters depth. The results were used to build sections and their interpretations allowed to conclude that the studied sedimentary sequence was deposited in delta and shorelines Quaternary environments.

The Pile Mound survey includes magnetometry paired with targeted ground-penetrating radar (GPR) and electromagnetic induction (EMI) surveys of the mound and testing of associated features over the ca. 6.5 ha site. The GPR survey discovered six rock features (five large rock features within the mound and one marking the outside of the mound). Knowledge of mounds in the Upper Cumberland Plateau (UCP) is lacking—the closest other studied sites are at the Corbin Site, Croley-Evans, Bell Site, and Beasley Mounds, approximately 75 – 100 km away. However, the most similar mound construction is found at Corbin and Cherokee sites, some 175 – 275 km away. In addition, the associated ceramic assemblage appears to reflect more similarity to the East Tennessee Valley rather than the Middle Cumberland region. These data provide a unique opportunity to better understand the Mississippian occupation in the UCP of Tennessee.

Pilot Valley, located in the eastern Basin and Range, north of Wendover, UT, contains numerous shorelines and depositional remnants of late Pleistocene Lake Bonneville. These remnants present classic ground penetrating radar (GPR) targets due to their coherent stratification, low clay, low salinity, and low moisture content. Three-dimensional (3D) GPR imaging can resolve fine-scale stratigraphy of these deposits down to a few centimeters. While lake levels fluctuated due to flooding events, climatic changes were the dominant factor in controlling lake levels. In Pilot Valley, the paleowind entered from the northwest, with storms coming from the south, and circulated clockwise around the basin, forming offshore sand bars. On the western side of the valley, a uniquely well-preserved interpreted regressive phase beach deposit, dated late Pleistocene, is hypothesized to have been a point bar shortly after the Provo Shoreline period. 3D GPR data, measured stratigraphic sections, cores, mineralogical analysis, and the collection of gastropod samples for radiocarbon dating constrain a reconstruction of the deposit's depositional environment and local paleoclimate for Lake Bonneville. The GPR images, visualized with state-of-the-art petroleum industry tools, reveal fine-scale stratigraphic detail that can be analyzed using seismic stratigraphy concepts. Our study provides a comprehensive model for ancient pluvial lake-shore depositional environments in a Basin and Range setting using an integration of geological and geophysical data.