An Effective Frequency Filtering Approach to Improve GPR Data Resolution Under the Concrete Pavements

This study focuses on developing the advanced analysis procedure for increasing the underground utility resolution using the RADAN software. The chop-off of the time-domain signal and frequency band filtering approach are adopted to improve underground utility resolution. The rebars of rigid pavement symbolically appear in the form of hyperbolic rings as an output of the GPR data. These small hyperbolic rings reduce the resolution of underground utilities, and further difficulty arises in identifying the appropriate location of underground utilities. Therefore, the resolution of underground utilities is compared with the proposed processing steps of frequency band filtering with the incremental and constant time chop-off approach. The incremental time chop-off approach results in a high resolution of underground utilities compared to the constant time chop-off approach in the GPRs output. The performance of the proposed processing steps is explored with the six different earth profiles. The findings of this study demonstrate that (1) GPR data collected using a 900 MHz antenna is highly sensitive, and removing the RADAN spectrum of rebars zone is an effective way for utility detection of depth less than 1 m, and (2) High rebars resolution is obtained using 900 MHz compared to 400 MHz.