| 摘要 |
A roadway ground penetrating radar system is provided for generating a continuous profile of the pavement structure. The profile shows individual layer and sub-surface anomaly depth and thickness. Radar signals are transmitted into the structure using a surface-coupled transmitter antenna and reflected waves are received by an array of surface-coupled receiver antennas located at different known spacings from the transmitter antenna. The different signal travel times are measured. An accurate measure (+/-5%) of signal velocity through each pavement layer can be calculated using the surface-coupled assembly spacing and travel time information. With the velocity accurately known at each sounding point, using conventional calculations one can determine interface depth and layer thickness, to an accuracy in the order of +/-5%. In a preferred embodiment, an air-launched "horn" antenna assembly is used in conjunction with the surface-coupled antenna assembly. The horn antenna assembly gives good resolution for layer thicknesses of about 50-100 mm; the surface-coupled antenna assembly gives good resolution for layer thicknesses greater than about 100-150 mm, and gives greater penetration depth. The system can be wheel mounted for advancing continuously along the roadway and the radar data can be synchronized with roadway location.
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