Ground-Penetrating Radar
GPR transmits radar pulses into the ground and records reflections from contrasts in dielectric permittivity. It offers the highest resolution of any surface method, at the cost of limited penetration in conductive ground; the balance between the two is set by antenna frequency and soil properties.
Learning Objectives
Undergraduate Core: By the end of this module, you will be able to:
- Relate dielectric permittivity and electrical conductivity to radar velocity and attenuation.
- Convert two-way travel time to depth using an independently constrained velocity.
- Fit a diffraction hyperbola and state the assumptions behind the estimate.
- Choose antenna frequency and recognize ringing, multiples, and conductive-ground limitations.
Graduate Extension
Analyze velocity uncertainty, migration, finite antenna separation, anisotropy, and the non-uniqueness of radar facies interpretation.
Practice this module Teach with active-learning slides
Topic Apps
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🖥️ Electromagnetic Physics: Conduction vs. Displacement
Why radar waves propagate in resistive ground and dissipate in conductive ground.
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Survey a synthetic subsurface and interpret the resulting radargram.
Demo
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⚡ Hyperbola Velocity Estimator
Fit a diffraction hyperbola on a radargram to recover wave velocity and target depth, the everyday calibration trick of GPR practice.
Classroom Lab
🧰 Depth uncertainty before excavation — compare dry- and wet-backfill velocity models, choose an antenna, and make a utility-safety recommendation from a depth range rather than one assumed value.