GPR signal attenuation through fragmented rock

This paper presents results on detecting large rock fragments in rock piles using ground penetrating radar (GPR). The authors are researching sensors to augment the image provided to the remote operator, assisting with detection of oversized fragments beneath the surface. The attenuation of the GPR signal was calculated over the band 0-3 GHz from the signal energy in the frequency domain. The results show that attenuation measurement allowed the samples which included a large fragment to be differentiated from samples only containing smaller rock fragments. By combining velocity analysis with attenuation the rock samples can be further differentiated from samples containing air pockets or irregular surfaces. The combination of attenuation and signal velocity allowed prediction rates to detect the presence of large rock fragments over 93% correctly in laboratory testing.