Analysis of time interpolation for enhanced resolution GPR data

In GPR applications where the antenna is subject to fast movement, vibration or rapid changes in the surface properties, it is desirable to decrease the time required to acquire a complete time domain trace to prevent the distortion of subsurface features between traces. One survey practice that can be adopted to minimize this effect is to decrease the number samples per trace during acquisition. This approach, however, decreases the precision of quantitative subsurface layer thickness measurements due to the timing uncertainty between samples. One processing method that can be applied to increase the measurement precision is interpolation along the time axis. Experiments were conducted to quantify the performance of two interpolation methods in which scans were acquired with both low and high number of samples per trace. The low resolution scans were interpolated to match the number of samples of the high resolution traces. The results show that there is a reduction in the target range error when interpolating along the time axis to increase the sampling resolution.