Table 1 Propagation speed values of the materials used in the experimental setups.
From: An Entropy-Based Propagation Speed Estimation Method for Near-Field Subsurface Radar Imaging
| Material | Propagation speed |
|---|---|
| Air | 3 × 108 m/s |
| Silica sand | 1.745 × 108 m/s |
| Desert sand | 1.89 × 108 m/s |