Study on Signal Processing of FMCW Ground Penetrating Radar

In this paper, a frequency-modulated-continuous-wave (FMCW) ground penetrating radar (GPR) is developed and used to measure the thickness of concrete/asphalt layers of highways/airports. If the thickness of the layer is thin, measurement may be impossible using traditional DFT method since the frequencies of reflected waves are very close and the week waves reflected from underground layers will be ldquosubmergedrdquo by the strong one reflected from the pavement surface. An adaptive filtering method is presented to eliminate the strong wave reflected from the pavement surface and thus the week waves reflected from the underground layer surfaces can be detected. Then the modified frequency estimation method is proposed to enhance the frequency estimation precision of FMCW GPR signal. Simulation experiment results have demonstrated the effectiveness of the proposed method.