scholarly journals Adaptive Ground Penetrating Radar Systems to Visualize Antipersonnel Plastic Landmines Based on Local Texture in Scattering / Reflection Data in Space and Frequency Domains

10.5772/7177 ◽  
2010 ◽  
Author(s):  
Yukimasa Nakano ◽  
Akira Hirose
Keyword(s):  
Ground Penetrating Radar ◽  
Local Texture ◽  
Reflection Data ◽  
Radar Systems ◽  
Frequency Domains ◽  
Ground Penetrating

scholarly journals Beach-ridge architecture constrained by beach topography and ground-penetrating radar, Itilleq (Laksebugt), south-west Disko, Greenland – implications for sea-level reconstructions.

2018 ◽  
Vol 66 ◽  
pp. 167-179
Author(s):  
Priscila E. Souza ◽  
Aart Kroon ◽  
Lars Nielsen
Keyword(s):  
Ground Penetrating Radar ◽  
Abrupt Change ◽  
Beach Ridge ◽  
Sediment Grain Size ◽  
Beach Ridges ◽  
Reflection Data ◽  
South West ◽  
Tide Level ◽  
Ground Penetrating ◽  
Reflection Characteristics

Detailed topographic data and high-resolution ground-penetrating radar (GPR) reflection data are presented from the present-day beach and across successive raised beach ridges at Itilleq, south-west Disko, West Greenland. In the western part of the study area, the present low-tide level is well defined by an abrupt change in sediment grain size between the sandy foreshore and the upper shoreface that is characterised by frequently occurring large clasts. The main parts of both fine and large clasts appear to be locally derived. Seaward-dipping reflections form downlap points, which are clearly identified in all beach-ridge GPR profiles. Most of them are located at the boundary between a unit with reflection characteristics representing palaeo-foreshore deposits and a deeper and more complex radar unit characterised by diffractions; the deeper unit is not penetrated to large depths by the GPR signals. Based on observations of the active shoreface regime, large clasts are interpreted to give rise to scattering observed near the top of the deeper radar unit. We regard the downlap points located at this radar boundary as markers of palaeo-low-tide levels. In some places, scattering hyperbolas are more pronounced and frequent than in others, suggesting differences in the occurrence of large boulders.

scholarly journals Frequency-dependent attenuation analysis of ground-penetrating radar data

Geophysics ◽  
2007 ◽  
Vol 72 (3) ◽  
pp. J7-J16 ◽  
Author(s):  
John H. Bradford
Keyword(s):  
Attenuation Coefficient ◽  
Ground Penetrating Radar ◽  
A Priori ◽  
Radar Data ◽  
Frequency Dependent ◽  
First Order ◽  
Reflection Data ◽  
Frequency Independent ◽  
Band Limited ◽  
Ground Penetrating

In the early 1990s, it was established empirically that, in many materials, ground-penetrating radar (GPR) attenuation is approximately linear with frequency over the bandwidth of a typical pulse. Further, a frequency-independent [Formula: see text] parameter characterizes the slope of the band-limited attenuation versus frequency curve. Here, I derive the band-limited [Formula: see text] function from a first-order Taylor expansion of the attenuation coefficient. This approach provides a basis for computing [Formula: see text] from any arbitrary dielectric permittivity model. For Cole-Cole relaxation, I find good correlation between the first-order [Formula: see text] approximation and [Formula: see text] computed from linear fits to the attenuation coefficient curve over two-octave bands. The correlation holds over the primary relaxation frequency. For some materials, this relaxation occurs between 10 and [Formula: see text], a typical frequency range for many GPR applications. Frequency-dependent losses caused by scattering and by the commonly overlooked problem of frequency-dependent reflection make it difficult or impossible to measure [Formula: see text] from reflection data without a priori understanding of the materials. Despite these complications, frequency-dependent attenuation analysis of reflection data can provide valuable subsurface information. At two field sites, I find well-defined frequency-dependent attenuation anomalies associated with nonaqueous-phase liquid contaminants.

scholarly journals Sources of backscatter at 5.3 GHz from a superimposed ice and firn area revealed by multi-frequency GPR and cores

2009 ◽  
Vol 55 (190) ◽  
pp. 373-383 ◽  
Author(s):  
Kirsty Langley ◽  
Pascal Lacroix ◽  
Svein-Erik Hamran ◽  
Ola Brandt
Keyword(s):  
Ground Penetrating Radar ◽  
Continuous Wave ◽  
Wave System ◽  
Air Bubble ◽  
Radar Systems ◽  
Impulse System ◽  
Polythermal Glacier ◽  
Bubble Number ◽  
Ground Penetrating ◽  
Previous Summer

AbstractWe investigate the major sources of backscatter at 5.3 GHz, within the superimposed ice and firn areas of a polythermal glacier. Two ground-penetrating radar systems, an 800 MHz impulse system and a polarimetric 5.3 GHz frequency-modulated continuous-wave system, are used to acquire along-glacier profiles in the accumulation area of Kongsvegen, Svalbard. The 800 MHz response is used to map reflection horizons in the glacier. Using cores from the superimposed ice and firn areas, the causes of these reflection horizons, in terms of snow, firn and ice layers, are investigated. Superimposing the reflection horizons on the co-polarized and cross-polarized 5.3 GHz profile, we are able to determine how the 5.3 GHz frequency responds to the different media. Scattering at rough interfaces and volume scattering occur in the superimposed ice area and are apparently caused by air-bubble number, size and distribution. In the firn the strongest return originates from below the previous summer surface, consistent with previous findings. At approximately the same depth, strong incoherent scattering begins. The rapid decrease in coherent reflections indicates the significance of scattering in the firn.

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