To detect overlapped echoes due to the thin pavement layers, we p resent a thickness measurement approach for the very thin layer of pavement structures. The term “thin” is relative to the incident wave length or pulse. By means of independent component analysis of noisy signals received by a single radar sensor, the overlapped echoes can be successfully separated. Once the echoes from the top and bottom side of a thin layer have been separated, the time delay and the layer thickness determination follow immediately. Results of the simulation and real data verify the feasibility of the p resented method.

       Key words: thin layer; thickness measurement; independent component analysis; ground penetrating radar;pavement