A new GPR calibration method for high accuracy thickness and permittivity measurement of multi-layered pavement

To improve the measurement accuracy for the layer thickness and the permittivity of multi-layered pavement, this paper proposes a new calibration method. Based on the layerstripping EM inversion, single or two calibrating coefficients are introduced into the calculation equations of thickness and permittivity. After the processing of calibration the nonlinear meaisurement errors. can be diminished effectively, and the accuracy of overlaid delamination can be improved. Moreover, the affection of calibration factors is discussed, and a lot of pavement data have been used to test and prove the performance of the calibration methods.