An investigation into the railway ballast dielectric properties using different GPR antennas and frequency systems

This paper presents an investigation into the relative dielectric permittivity of railway ballast using ground-penetrating radar (GPR). To this effect, experimental tests are carried out using a container (methacrylate material) of the 1.5 × 1.5 × 0.5 m dimensions. GPR systems equipped with different ground-coupled and air-coupled antennas and central frequencies of 600 MH, 1000 MHz, 1600 MHz and 2000 MHz (standard and low-powered antenna systems) are used for testing purpose. Several processing methods are applied to assess and compare the dielectric permittivity of the ballast system under investigation. Comparison of results identifies critical factors as well as antennas and central frequencies most suitable for the purpose.