KEYWORDS: Global Positioning System, Roads, General packet radio service, Content addressable memory, Radar, Geographic information systems, Cameras, Video, Data acquisition, Antennas
At the moment of carry out a study with ground penetrating radar (GPR) it is interesting to count with the support provided by other information sources. All the available information relative to the study area will be valuable in the subsequent phases of processing and interpretation of the obtained GPR records. Nowadays there is a logical trend to the integration of GPS devices. The decrease in size of these equipment, the increase of their accuracy and new wireless communication technologies (802.11, Bluetooth,...) encourage this incorporation. GPR/GPS integration allows an accuracy positioning of the radar data under favourable conditions. Furthermore it brings the possibility to import this data into a geographic information system (GIS). This study deepens the process of integration of both technologies applied to road evaluation. To the accomplishment of this study, a dual frequency (L1+L2) RTK GPS, two Bluetooth GPS receivers (with SiRF chip) admitting both real time differential corrections (SBAS), and a GPS receiver with post-processed sub-meter accuracy were used. As regards GPR equipment, shielded 500, 800 and 1000 MHz antennas were used in different configurations.
KEYWORDS: Antennas, General packet radio service, Radar, Radar imaging, Sensors, Contamination, Imaging systems, Electromagnetism, Global Positioning System, 3D image processing
Prestige fuel oil tanker was damaged during a storm in November 13rd, 2002, close to the coast of Galicia (Spain). After some days the Prestige broke in half and sank, leaking about 40.000 tons of oil which affected more than 1.000 km of the coast in Spain, Portugal and France. Some months later, layers of fuel contamination still appear at different depths in the sand of the beaches. The tidal process is that the first tide brings fuel over the sand but, if it is not removed, following tides place clean layer of sand on the top of fuel, and the beaches appear to be clean. Layers of fuel appears at different depths in the sand, from some cm to 1-2 meters. The lateral extent of the contamination also varies from some cm to more than 1 m. Radar sensors could be used in-situ to detect and imaging fuel layers below sand in some inland areas, which are under the influence of high winter tides but remain out of the influence of salt water from the sea during spring and summer time. This study show some tests carried out on the beaches with a ground-penetrating radar system operating with 500 & 800 MHz nominal frequency antennas, and a study case made in the beach of Carnota (Galicia) where it was possible to detect an imaging a buried fuel layer 6 months later.
In Spain there are more than 500,000 ha of Eucalyptus plantations. These represent 3,5% of the national forest and the 25% of the timber harvested. Galicia monocultures of Eucalyptus globulus Labill. plantations cover 177,679 ha, and mixed stands of eucalyptus cover 200,000 ha more. This high productivity has been powered by the absence of pests and pathogens. However, since 1991 the health and productivity of these stands has been threatened by the Eucalyptus snout beetle (Gonipterus scutellatus Gyll.), which causes a severe defoliation to eucalyptus stands in Galicia.
The aim of this paper is to establish a workflow to locate the areas affected by the defoliator, and determinate the basics patterns of spatial distribution, in order to predict future hot spots and develop more integrated pests management. This information will be part of a wider Information System, develop to improve the forest management and monitoring of these stands. The damaged area and the level of defoliation will be mapped using satellite imagery. The additional information of stand conditions, such as site index, climate and microclimatic conditions, digital terrain model, dendrometric and dasometric variables, will be integrated also in a Geographical Information System.
KEYWORDS: Radar, General packet radio service, Photogrammetry, Reflectors, Antennas, Cultural heritage, Digital photography, Ground penetrating radar, Visualization, 3D modeling
The importance of archaeological heritage justifies looking for new techniques and methods which allow their knowledge in a more exhaustive way. We are not only talking about detection, but also about remains geometry and construction details. Cultural heritage record documents should include all possible information and the collection of this non-destuctive techniques information is recommended (Neubauer, 2001). In this work we show the preliminary results obtained applying three techniques at an archaeological site in Galicia (Spain), in order to document the remains of a megalithic tomb. First of all, a full topographic total station survey was made to obtain a digital terrain model of the studied area. The GPR investigation was made with Zond- 12c equipment operating with a 900 MHz antenna, radargrams were corrected with the digital terrain data attained hefore. The results showed a very shallow reflector on the top of a small hummock (15 m diameter, 3 m high), very close to an emerging flagstone which could be a part of the tomb. Excavation makes evident the presence of some other flagstones of the tomb at this point. The full archaeological site was excavated and a close-range photogrammetric study was made to obtain a cultural heritage record document including all possible metric information of the remains. A calibrated digital camera was used to obtain the spatial representation of the tomb. This information may be used in the future to reconstruct the tomb in another place, because the contruction of a new highway crossing at this archaeological site is going to take place at some future stage.
This paper presents a geophysical survey, which is being carried out with the use of the Ground Penetrating Radar (GPR) in an ornamental rock quarry located at Santo Antonio de Pádua area, northwest of Rio de Janeiro State, Brazil. The quarry is settled in a milonitic rock belt. It is exploited the "olho de pombo" rock, which is in commercial demand, in Brazil and abroad. The purpose of the investigation is to test the applicability of the GPR technique in order to determine the thickness of the sterile material, and the fractures within the rock massif from where the rock blocks are taken. However it will be discussed the results of two radargrams obtained on the rock without altered cap rock The study is developed with the partnership of the Centro de Tecnologia (Mineral Technology Center - CETEM), which has a great experience in deals with ornamental rock research. The acquired data were processed with the use of the software GRADIX® (version 1 . 1 1 — Interpex) in order to enhance the anomalies and the stratigraphy it was generated originated sections, with average depth of 20 meters. In the surveys it was utilized 100 MHz frequency antennae. It is intended to build a work methodology for the local mining operator in order to contribute to reduce the environmental impact problems, which in general occur within this kind of activity. It was possible to identify the fractures and also the weathering cover thickness. Presently, the requirements of govemmental institutions, the environmental impact caused by ornamental rock mining, occupy increasing distinction within mineral exploiting industry. The survey presented higer quality results.
KEYWORDS: General packet radio service, Reflectors, Water, Chemical elements, Radar imaging, Antennas, Electromagnetism, Dielectrics, Radar, Signal attenuation
A study using GPR has been carried out at Itaipuaçu beach,Marica, Rio de Janeiro with the aim of reconstructing and analysing the environment of depositing sediments. Fifty profiles were made using a 200 MHz bistatics antennas (nominal frequency). These profiles generated a 3D cube. In the same way, we obtained an estimation of propagation velocity of the signal in the subsoil (by CMP technique) using two 80 Mhz antennas. The analysis of the radargrams allows to recognize the stratigraphic sequence and its progradation. Through core drill sampling in the investigation site, it has been possible to establish a correlation between some reflections and the presence of organic matter, and to make evident that the salt content of water below the water table increases with depth. With these profiles we can see the progradations, and under the water table, a reflector which seems to be caused by the combination of organic matter, together with a sharp increase in the salt content of the water. This interpretation agrees with the model "Ghyben-Herzberg fresh-water lens" Hagrey & Müller,( 2000), as well as other results obtained by these authors.
KEYWORDS: Reflectors, Signal attenuation, Radar, Ray tracing, Data acquisition, Reflection, Antennas, Radar signal processing, Receptors, Electromagnetism
In different places of Morelia, Michoacan, Mexico, there are evidences of four active geologic creep-faults system in. These events have damages (cracking and landslides) in the civil building (Garduno M., et. al, 1998; Garduno M., et. al, 1999; Lermo S., et. al., 1999). In order to find these structures in the first 10 m of depth, region where we have the influence in civil building, we carried out a geophysical study with georadar technique. We made 15 sounding in the fault zone to join the results to preliminar geologic studies in order to improve the security rules in the high risk places. In this work we show the results of three sounds with georadar, as well as the final Bidimensional Model effected with the technique of tracing of ray.
This paper describes a GPR study carried out with the aim of evaluating deterioration of concrete floors in textile factories. During some years, spillages from the production process were split onto the floor of the factory. The slow but continue action of these spillages in the concrete caused an important variation in its porosity, which could be detected by studying changes in GPR reflected pulse. A simple synthetic model was developed in order to obtain information about how the response of GPR antenna pulse is depending on changes in the porosity of concrete. We also take into account the different conditions of the factory floor at the moment (since many years ago it's been isolated from the action of the spillage). The heterogeneous conditions of the floor and the simplicity of the model used did not allow for an accurate estimation of porosity, but it was possible to map degraded areas on the floor related to changes in the reflected signal. Core drills made later confirmed in some of them a concrete porosity of up to 25%, closer to that of sand than to concrete.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.