Abstract
Finite-Difference Time-Domain (FDTD) modelling of Ground Penetrating Radar (GPR) is becoming regularly used in model-based interpretation methods like full waveform inversion (FWI), and machine learning schemes using synthetic training data. Oversimplifications in such forward models can compromise the accuracy and realism with which real GPR responses can be simulated, and this degrades the overall performance of the aforementioned interpretation techniques. Therefore, a forward model must be able to accurately simulate every part of the GPR problem that can affect the resulting scattered field. A key element is the antenna system and excitation waveform, so the model must contain a complete description of the antenna including the excitation source and waveform, the geometry, and the dielectric properties of materials in the antenna. The challenge is that some of these parameters are not known or easily measured, especially for commercial GPR antennas that are used in practice. We present a novel hybrid linear/non-linear FWI approach which can be used, with only knowledge of the basic antenna geometry, to simultaneously optimise the dielectric properties and excitation waveform of the antenna, and minimise the error between real and synthetic data. The accuracy and stability of our proposed methodology is demonstrated by successfully modelling a Geophysical Survey Systems (GSSI) Inc. 1.5~GHz commercial antenna. Our framework allows accurate models of GPR antennas to be developed without requiring detailed knowledge of every component in the antenna. This is significant because it allows commercial GPR antennas, regularly used in GPR surveys, to be more readily simulated.
Original language | English |
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Pages (from-to) | 1768-1778 |
Number of pages | 11 |
Journal | IEEE Transactions on Geoscience and Remote Sensing |
Volume | 57 |
Issue number | 3 |
Early online date | 27 Sept 2018 |
DOIs | |
Publication status | Published - Mar 2019 |
Keywords
- Antennas
- commercial
- Dielectrics
- Finite difference methods
- finite-difference time-domain (FDTD)
- full-waveform inversion (FWI)
- Ground penetrating radar
- ground-penetrating radar (GPR)
- hybrid optimization
- linear inversion
- nonlinear inversion
- Numerical models
- Optimization
- Time-domain analysis