Maximum likelihood method for time-delay estimation of multiple echoes

When the ground-penetrating radar (GPR) is used as a non-destructive testing method in the field of civil engineering, the thickness of the mediums can be deduced from radar profiles by echo detection, which provides the time-delay estimation (TDE) associated with each interface. In order to improve the performance of TDE, this paper proposes a new technique based on maximum likelihood principle for estimating the time delays. The proposed method takes into account the multiple echoes phenomena of the propagation of underground wave.