scholarly journals Step-Frequency Ground Penetrating Radar for Agricultural Soil Morphology Characterisation

2019 ◽  
Vol 11 (9) ◽  
pp. 1075
Author(s):  
Federico Lombardi ◽  
Maurizio Lualdi
Keyword(s):  
Ground Penetrating Radar ◽  
Precision Agriculture ◽  
Continuous Wave ◽  
Textural Properties ◽  
Electromagnetic Properties ◽  
Soil Morphology ◽  
Agricultural Field ◽  
Step Frequency ◽  
Imaging Results ◽  
Ground Penetrating

Soil morphology plays a fundamental role in the vertical and lateral movements of solutes and water transport, providing knowledge regarding spatial distribution of its textural properties and subsurface dynamics. In this framework, the measured values of electrical conductivity are able to reveal the heterogeneity of soil that is present in a particular agricultural field and they are affected by more than one important physical characteristic: soil texture, organic matter, moisture content, and the depth of the clay pan. In the microwave region, these dynamics are known to exhibit a frequency dependent behaviour. This study explores the application of a Step Frequency Continuous Wave Ground Penetrating Radar (SFCW GPR) to shed light on the practical impact that these dependencies have on the imaging results, not only regarding the electrical characterisation of the subsurface morphology, but also in its correct interpretation. This information is of notable importance for determining water-use efficiency and planning precision-agriculture programs. The results clearly show visible and significant fluctuations of the amplitude levels, depending on the considered central frequency, demonstrating that the frequency dependence of electromagnetic properties of heterogeneous soil are significant and cannot be ignored if the aim is to properly define the subsurface attributes. The measurements also suggest that correlating the delineated variations might help in the identification of extended features and the classification of areas that possess similar properties in order to increase the confidence in monitoring soil resources.

scholarly journals An Improved Modified Universal Ultra-Wideband Antenna Designed for Step Frequency Continuous Wave Ground Penetrating Radar System

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1045 ◽  
Author(s):  
Yuxuan Wu ◽  
Feng Shen ◽  
Yue Yuan ◽  
Dingjie Xu
Keyword(s):  
Ground Penetrating Radar ◽  
Continuous Wave ◽  
Soil Surface ◽  
Antenna System ◽  
Ultra Wideband ◽  
Step Frequency ◽  
Uwb Antenna ◽  
Ground Penetrating ◽  
Better Than ◽  
Bow Tie

Step Frequency Continuous Wave Ground Penetrating Radar (SFCW-GPR), as a tool for nondestructive testing of shallow soil surface targets, the realization of the function of SFCW-GPR is mainly based on the theory of refraction, reflection and scattering of electromagnetic wave in the discontinuity of dielectric constant. So, the UWB antenna system, an important part of SFCW-GPR, becomes more indispensable. In this paper, an improved modified universal antenna is designed, simulated and fabricated. Based on a typical Bow-tie antenna, it is modified by the methods of lumped loads, cavity-backed loading and structure loading. The simulated and measured results show that the UWB antenna has 1.36 GHz bandwidth from 0.64 to 2.0 GHz with three resonant wavelength peaks, and having been modified and improved, the UWB antenna performances including voltage standing-wave ratio (VSWR), input impedance, the boresight gain and current distribution, are much better than the typical Bow-tie antenna. In addition, the results of verification experiment of Step Frequency Continuous Wave (SFCW) show that the antenna can be applied to the working scenarios of SFCW-GPR.

scholarly journals Ground Penetrating Radar Survey of the Floor of the Accademia Gallery (Florence, Italy)

2021 ◽  
Vol 13 (7) ◽  
pp. 1273
Author(s):  
Lapo Miccinesi ◽  
Alessandra Beni ◽  
Silvia Monchetti ◽  
Michele Betti ◽  
Claudio Borri ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Air Conditioning ◽  
Underground Structure ◽  
Step Frequency ◽  
Ground Floor ◽  
The Public ◽  
Ground Penetrating

This paper reports the results of a ground penetrating radar (GPR) survey of the ground-floor of Academia Gallery (Florence, Italy) where the Michelangelo’s David is exhibited to the public. The equipment used was a step-frequency GPR operating in the 100 MHz-1 GHz band, named ORFEUS. The survey covered an area of 13 m × 7.3 m, and the scans were performed along two orthogonal directions. Acquisitions in the same direction were separated by 0.25 m from each other. The GPR was able to confirm the underground structure, as it can be deducted by planimetry and historical documentation. In particular, the radar clearly detected the air-conditioning ducts under the floor and an approximately circular foundation below the basement of the statue.

scholarly journals Imaging Thermal Anomalies in Hot Dry Rock Geothermal Systems from Near-Surface Geophysical Modelling

2019 ◽  
Vol 11 (6) ◽  
pp. 675 ◽  
Author(s):  
David Gomez-Ortiz ◽  
Isabel Blanco-Montenegro ◽  
Jose Arnoso ◽  
Tomas Martin-Crespo ◽  
Mercedes Solla ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Electromagnetic Induction ◽  
Hydrothermal Systems ◽  
Ground Temperature ◽  
Geothermal Systems ◽  
Near Surface ◽  
Hot Dry Rock ◽  
Ground Temperatures ◽  
Imaging Results ◽  
Ground Penetrating

Convective hydrothermal systems have been extensively studied using electrical and electromagnetic methods given the strong correlation between low conductivity anomalies associated with hydrothermal brines and high temperature areas. However, studies addressing the application of similar geophysical methods to hot dry rock geothermal systems are very limited in the literature. The Timanfaya volcanic area, located on Lanzarote Island (Canary Islands), comprises one of these hot dry rock systems, where ground temperatures ranging from 250 to 605 °C have been recorded in pyroclastic deposits at shallow (<70 m) depths. With the aim of characterizing the geophysical signature of the high ground temperature areas, three different geophysical techniques (ground penetrating radar, electromagnetic induction and magnetic prospecting) were applied in a well-known geothermal area located inside Timanfaya National Park. The area with the highest ground temperatures was correlated with the location that exhibited strong ground penetrating radar reflections, high resistivity values and low magnetic anomalies. Moreover, the high ground temperature imaging results depicted a shallow, bowl-shaped body that narrowed and deepened vertically to a depth greater than 45 m. The ground penetrating radar survey was repeated three years later and exhibited subtle variations of the signal reflection patterns, or signatures, suggesting a certain temporal variation of the ground temperature. By identifying similar areas with the same geophysical signature, up to four additional geothermal areas were revealed. We conclude that the combined use of ground penetrating radar, electromagnetic induction and magnetic methods constitutes a valuable tool to locate and study both the geometry at depth and seasonal variability of geothermal areas associated with hot dry rock systems.

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