Hyperbolic Reflection
Definition
The bowtie-shaped pattern in a GPR time section produced as the antenna passes over a point-like object. The shape is governed by the wave velocity in the host medium, making it a useful calibration target for depth estimation.
- Shape
- Bowtie pattern in the GPR time section
- Governing factor
- Wave velocity in the host medium (soil)
- Use
- Calibration target for converting travel time to depth
- Related term
- Same phenomenon described as a hyperbolic anomaly on the radargram
Common questions
Is a hyperbolic reflection the same thing as a hyperbolic anomaly?+
They describe the same curved response to a point target, but hyperbolic reflection emphasises the raw time-domain signal physics used for velocity calibration, while hyperbolic anomaly is the term used when discussing the feature as evidence of a possible buried object on the finished radargram.
Why does soil type affect how sharp a hyperbolic reflection appears?+
Wet clay attenuates and scatters the radar signal much more than dry sand, so the same buried target can produce a crisp, well-defined hyperbola in sandy soil and a weak, smeared one in saturated clay-rich ground.
Related terms
- Attenuation
- The reduction in radar signal amplitude with distance traveled. Electrically conductive materials (wet clay, saline soil) convert signal energy to heat, limiting...
- Dielectric Permittivity (Epsilon)
- A material property that controls how fast electromagnetic waves travel through it and how strongly they reflect at a boundary. Water has...
- Migration
- A processing step that repositions reflections from their apparent location (a spread-out hyperbola) to their true subsurface location (a point or plane),...
- Time Window
- The total two-way travel time recorded by the GPR per trace, effectively setting the maximum depth sampled. The time window must be...
- Velocity Calibration
- The process of estimating the true electromagnetic wave velocity in the survey soil, usually by fitting a hyperbola to a known reflector...