Assessment of ballast layer under multiple field conditions in China

Ballast layer condition should be more regularly and accurately inspected to ensure safe train operation; however, traditional inspection methods cannot sufficiently fulfil this task. This paper presents a method of ground penetrating radar (GPR) application to reflect ballast layer fouling levels under diverse field conditions (annual gross...

Ballast fouling inspection and quantification with ground penetrating radar (GPR)

Ground penetrating radar (GPR) has been applied for ballast layer inspection for two decades, mainly for the analysis of ballast layer fouling levels. However, some issues that affect the inspection quality remain unsolved, such as issues involving the GPR equipment quality (antenna) and the correlation between the GPR indicator and fouling...

Railway ballast layer inspection with different GPR antennas and frequencies

Ground penetrating radar (GPR) is a popular technology for inspecting railway ballast layer, mainly on the ballast fouling level. However, different GPR antennas with different frequencies are suitable for different inspection emphasis and diverse railway lines (weather and sub-structure). In addition, the full-scale track model (with...

Forward-Looking GPR Imaging with Near-Optimal 3-D Synthetic Array

In this paper, we propose an Elevation-Radial scanned Synthetic Aperture Radar (E-RadSAR) for forward-looking ground penetrating radar (GPR) imaging. The E-RadSAR exploits the advantages of both RadSAR and Elevation-Circular SAR (E-CSAR) by utilizing the SAR technique in the cross- and down-range directions for signal acquisition. It could be...

Forward-Looking Ultra-Wideband Synthetic Array Imaging

The expansion of microwave imaging applications in various fields proposes increasingly higher requirements (including spatial resolution, dynamic range, and signal-to-noise ratio) for microwave imaging systems. To achieve high-quality imaging, microwave imaging systems generally exploit spatial-, frequency- and polarization-diversities to probe...

Efficient Implementation of GPR Data Inversion in Case of Spatially Varying Antenna Polarizations

Ground penetrating radar imaging from the data acquired with arbitrarily oriented dipole-like antennas is considered. To take into account variations of antenna orientations resulting in spatial rotation of antenna radiation patterns and polarizations of transmitted fields, the full-wave method that accounts for the near-, intermediate-, and...