wavelet transform;  ground penetrating radar;  signal processing;  Mallat algorithm;  Wavelet packet algorithm

The pulsed GPR echo signal is a typical non-stationary and nonlinear signal, and the sampling signal inevitably carries various noises, which need to be properly processed. Wavelet transform has good time-frequency locality and is one of the effective tools for analyzing non-stationary signals. The basic theory of wavelet transform is systematically expounded, and the measured signal of radar detection of pavement thickness is analyzed and processed by Mallat algorithm and wavelet packet algorithm, and then the pavement layer thickness is calculated, and finally the calculation result is compared with the actual thickness. The comparative results show the effectiveness of wavelet analysis in road GPR echo signal processing.