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In order to predict the collapse of a tree, it is necessary to investigate its internal parts. To perform such investigation without harming the tree, ground penetrating radar (GPR) appears to be a promising non-invasive technique. The objective of this study is the investigation of particular features occurring in tree trunk radar images, due to the circumferential data acquisition. This study is...
GPR has emerged as one of the most relevant NDT technologies, which can be employed in various civil engineering (CE) applications. While the general applicability of GPR has been demonstrated, an objective evaluation of the limitations of GPR for qualitative inspection tasks is still missing. Therefore, the POD method, based on the “â vs. a” approach, was transferred to the application of GPR for...
Ballast material typically employed in rail track bed construction has been herein physically and electromagnetically characterized. Several ground-penetrating radar (GPR) tests have been carried out in a laboratory environment, wherein a proper set-up was realized. Four GPR systems comprising five different central frequencies of investigation have been used for the measurements. The impacts brought...
It is well known, that the antenna polarization is a relevant parameter for the inspection of different orientations of rebars. In particular, an electric field that is parallel to the rebar orientation will result in a reflection that is much stronger than one caused by an electric field that is orthogonal to the rebar orientation. When horn antennas are used, it can be shown that both rebar orientations...
In this work, the evolution of damages in pavement life cycle relative to rutting has been modeled in relevant pavement sections. Ground-penetrating radar (GPR) surveys were carried out at the rural road network scale using an air-launched pulsed radar system, 1GHz central frequency of investigation, linked to an instrumented van for collecting data at traffic speed. Surveys were performed in two...
A novel ellipse cavity-backed and slot-tuned bow-tie antenna was designed to facilitate the application of ultra-wide band (UWB) ground penetrating radar (GPR) in low frequency. Lumped resistor loading was applied at the end of antenna arms to broaden the impedance bandwidth. Taper tuned method was also used to optimize the current distribution. Antenna characteristic was analyzed by simulation. Finally,...
This paper presents a compartmental filtering method to improve signal-to-noise ratio (SNR) of the radio-echo sounding (RES) data of ice sheets while preserve weak signals in the deep layers. The proposed method performs local low-rank filtering on different internal layers of ice sheet to avoid weak signals from being filtered by global denoising methods. Experimental results show that the proposed...
Presents the introductory welcome message from the conference proceedings. May include the conference officers' congratulations to all involved with the conference event and publication of the proceedings record.
We have published a ground-coupled GPR antenna array, which consists of one transmitter and five receivers, for in situ estimation of the thickness and dielectric permittivity of an asphalt pavement layer [1]. In this paper, we optimize the design of the antipodal Vivaldi antenna to pursue a higher resolution through reducing the late-time ringing. Furthermore, an off-ground antenna array is assembled,...
This paper studies the effects of relatively homogeneous (RHWD) and relatively inhomogeneous water distributions (RIWD) in soil compared by varying the water content through a wetting and drying cycle in a tank (1.85m long × 1.55m wide × 1m deep) filled with 750mm thick plant soil. During the cycle, a 900MHz antenna was regularly used to capture GPR radargrams on a buried steel pipe. Hyperbolic reflections...
Road operation in areas with frozen soils requires monitoring of subgrade soils due to seasonal changes of their properties as well as development of negative cryogenic processes. Monitoring subgrade soil properties and condition is most effective using GPR. The results of theoretical and experimental studies of subgrade soils of roads in the North revealed the main wave characteristics of GPR data...
Compared with a conventional single-channel GPR system, a GPR system with a multi-input and multioutput (MIMO) antenna array is not only more efficient in 3D data acquisition, but also allows the collection of a multi-offset dataset, thereby providing additional information for more effective subsurface imaging. We develop a three-dimensional (3-D) reverse time migration (RTM) algorithm for processing...
A two-dimensional finite element time domain (FETD) algorithm for simulation of ground penetrating radar (GPR) on an anisotropic medium with conductive loss is described. In this algorithm, the finite element method is used to discretize computational area by using the unstructured Delaunay mesh and Newmark difference method for time discretization. The anisotropy of the medium is modeled be orthorhombic...
We investigate the development of passive cooperative targets as sub-surface sensors interrogated by Ground Penetrating RADAR (GPR). Using piezoelectric substrates for converting the incoming electromagnetic pulse to an acoustic wave confined to the sensor surface (Surface Acoustic Wave transducer — SAW) allows for shrinking the sensor dimensions while providing sensing capability through the piezoelectric...
An ice road will be organized across bodies of water in winter to enable the movement of vehicles and people, thus creating the proper living and operating conditions for the local population and industry. Possible loads and measures necessary to ensure the rigidness of the ice must be considered when setting up such crossings. This article produces the results of research on the ice crossings using...
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