What are GPR Cross-Section and Back-Scatter Gain?
The cross-section is a measure of the effective area that a scatterer projects into the path of the incident radar signal. The incident radar wavefront energy per unit area multiplied by the cross-sectional area determines the energy the scatterer extracts from the incident wave. Figure 5: Illustration of scattering cross-section area and back-scatter gain. In (a) a large area is presented and most energy directed back. In (b) the target presents a small cross-section and the scattered signal is not directed back to the receiver. The energy extracted signal can be absorbed or re-radiated in any direction. Back-scatter gain measures the amount of energy re-radiated back in the direction of the incident signal as depicted in Figure 5. Back-scatter gain and cross-sectional area are either computed from numerical modelling or measured for standard geometrical shapes in laboratories. Some simple geometries yield relatively compact analytical back-scatter gain formulas. The cross-sectional a
