What Is Ground Penetrating Radar (GPR)? How It Works & Uses

Ground Penetrating Radar (GPR) is a geophysical device that lets you see inside concrete structures and the ground non-destructively. It emits electromagnetic waves to detect rebar, voids, buried pipes and cables. This guide explains how GPR works, where it is used and what to consider when renting a unit.

How does GPR work?

A GPR device sends high-frequency electromagnetic waves (typically 100 MHz – 2.6 GHz) through an antenna. These waves reflect off materials of different density (concrete, steel rebar, voids, water). By measuring reflection times and amplitudes, the device renders a cross-section of the subsurface as a radargram. Higher frequencies show shallow detail; lower frequencies reach deeper.

What is GPR used for?

Main uses: rebar detection and cover measurement in reinforced concrete, locating post-tension cables, finding buried pipes and cables, inspecting road and bridge layers, non-destructive archaeological surveys and detecting subsurface voids. It is often used to reduce risk before drilling, cutting or coring.

Advantages and limitations

The advantage is fast, non-destructive, real-time results — you see inside without damage. Limitations depend on the material: clayey, conductive soils and densely reinforced concrete attenuate the signal, reducing depth and resolution. Correct interpretation requires an experienced operator and the right antenna frequency.

What to check when renting a GPR

The job type drives device choice: rebar scanning needs a high-frequency unit (e.g. 1.6–2.6 GHz), deep soil surveys need a low-frequency system. When renting, ask about calibration, antenna frequency range, software/report support and operator service if needed. On Tenderely you can contact the owner directly to clarify price, delivery and technical support.

Frequently Asked Questions