Off-Grid Time-Delay Estimation for Ground Penetrating Radar: A Nested Sampling Based Block Sparse Representation Method

In this paper, we propose a nested sampling based off-grid block sparse representation method (Nested-OGBSR) for time-delay estimation (TDE) of coherent ground penetrating radar (GPR) backscattered echoes. Nested sampling strategy is taken to reduce the sampling rate and computational burden. The off-grid data model is adopted to eliminate the effect of basis mismatch caused by the predefined grids in sparse representation (SR) and thus improve the estimation accuracy. The non-circularity of GPR signals is also utilized to enhance the temporal resolution of sparse block representation (BSR). Numerical and experimental results are provided to show the superiority of the proposed method in terms of estimation accuracy, temporal resolution and computational complexity.