Antennas

Daniels, David J.

doi:10.1016/b978-0-444-53348-7.00004-1

Cited by 35 publications

(40 citation statements)

References 25 publications

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“…However, for a given wave length, resolution decreases with depth (i.e. increasing size of footprint with time, Daniels, 2009). The strong decrease in amplitudes with increasing depth of reflections is mainly controlled by attenuation of the energies of the electromagnetic waves due to conductive electrical properties of the different sediments.…”

Section: Gpr and Radar Faciesmentioning

confidence: 99%

Three-dimensional high resolution fluvio-glacial aquifer analog: Part 1: Field study

Bayer

Huggenberger

Renard

et al. 2011

Journal of Hydrology

100

106

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s u m m a r yDescribing the complex structures that exist in many sedimentary aquifers is crucial for reliable groundwater flow and transport simulation. However, hardly any aquifer can be inspected in such detail that all decimeter to meter heterogeneity is resolved. Aquifer analogs serve as surrogates to construct models of equivalent heterogeneity, and thus imitate those features relevant for flow or transport processes. Gravel pits found in excavation show excellent sections of the sedimentary sequence and thus offer direct insight into the structural and textural composition of the subsoil. This paper describes an approach to also inspect the third dimension: by mapping during the ongoing excavation it is possible to obtain a three-dimensional representation of the subsurface within a short period of time. A detailed description of a case study is presented and the findings from sedimentological, hydrogeological and geophysical analyses are compared. The gravel pit is located near the town of Herten in southwest Germany, where relatively young unconsolidated fluvio-glacial and fluvial sediments in the Rhine basin are mined. The excavated gravel body is built up by architectural elements typical for braided river deposits. The study generated a high-resolution data set of lithofacies, hydrofacies and ground penetrating radar (GPR) profiles. It represents the basis for a full three-dimensional geostatistical reconstruction presented in the second part

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Section: Gpr and Radar Faciesmentioning

confidence: 99%

Three-dimensional high resolution fluvio-glacial aquifer analog: Part 1: Field study

Bayer

Huggenberger

Renard

et al. 2011

Journal of Hydrology

100

106

View full text Add to dashboard Cite

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“…Thus, the values of a that are based on the former most closely match the bandwidth of the GPR data which were collected using an antenna with central frequency (air based) of 500 MHz with approximate bandwidth of 250 to 750 MHz. Note that a reduced effective bandwidth is expected when coupled to a lossy ground which acts as a low-pass filter with attenuation of higher frequencies (Daniels, 2009). values of relative permittivity ( r) that have been obtained from the literature for several relevant geological materials are also listed.…”

Section: Time-domain Reflectometrymentioning

confidence: 99%

Subsurface imaging a Viking-Age churchyard using GPR with TDR: Direct comparison to the archaeological record from an excavated site in northern Iceland

Damiata

Steinberg

Bolender

et al. 2017

Journal of Archaeological Science: Reports

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The results of a ground-penetrating radar (GPR) survey over a Viking-Age Christian churchyard (ca. AD 1000-1100) that was subsequently fully excavated are reported. During excavation, broadband time-domain reflectometry (TDR) measurements of apparent relative permittivity were made of various features which helped to constrain interpretations of the radar data. Although four probes of different lengths were used (0.1, 0.15, 0.2 and 0.3 m), the longest waveguide yielded effective frequencies that most closely matched the bandwidth of the radar data, which was collected using a 500 MHz antenna. The excavation revealed 25 graves. Comparison of the radar data to the archaeological record indicated that all graves containing skeletal remains produced signatures from the bones, but only half of those were interpreted as such prior to excavation. The skeletons of three adults

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“…The DDS can generate a wideband chirp from 0 to 400 MHz, with a high rate and high linearity due to a digital generation. High linearity frequency sweep generation is essential for FM-CW systems, because they are extremely sensitive to linearity errors in the frequency ramp, which produces range side-lobes and therefore resolution degradation (Daniels, 2004). High rate sweep generation is necessary for fast surveys, such as airborne radar systems.…”

Section: Signal Generationmentioning

confidence: 99%

A low power consumption radar system for measuring ice thickness and snow/firn accumulation in Antarctica

Uribe¹,

Zamora²,

Gacitúa³

et al. 2014

Ann. Glaciol.

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ABSTRACT. In order to measure total ice thickness and surface snow accumulation in Antarctica, we have designed and built a surveying system comprising two types of radar. This system is aimed at having low power consumption, low weight/volume and low construction cost. The system has a pulsecompression radar to measure ice thickness, and a frequency-modulated continuous wave (FM-CW) radar designed to measure hundreds of meters of surface snow/firn layers with high resolution. The pulsecompression radar operates at 155 MHz, 20 MHz of bandwidth; and the FM-CW radar operates from 550 to 900 MHz. The system was tested in December 2010 at Union Glacier (79846 0 S, 83824 0 W), West Antarctica, during an oversnow campaign, where Union and other nearby glaciers (Schanz, Schneider and Balish) were covered through 82 km of track. Ice thickness of 1540 m and snow/firn thickness of 120 m were detected in the area. The collected data allowed the subglacial topography, internal ice structure, isochronous and the snow/ice boundary layer to be detected. Here we describe radar electronics, their main features and some of the results obtained during the first test campaign. Further improvements will focus on the adaptation of the system to be implemented on board airplane platforms.

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Antennas

Cited by 35 publications

References 25 publications

Three-dimensional high resolution fluvio-glacial aquifer analog: Part 1: Field study

Three-dimensional high resolution fluvio-glacial aquifer analog: Part 1: Field study

Subsurface imaging a Viking-Age churchyard using GPR with TDR: Direct comparison to the archaeological record from an excavated site in northern Iceland

A low power consumption radar system for measuring ice thickness and snow/firn accumulation in Antarctica

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