How ground-penetrating radar works

Monitor

GPR transmitter/

receiver unit

Trench

1

2

The GPR transmitter

emits pulses of electromagnetic energy into the subsurface

Objects or disturbances in the soil reflect patterns of energy back to the GPR receiver

Operator makes

multiple passes

over search grid

Water pipe

3

4

Different materials vary in their resistance to the electric field, to return distinct signals

The GPR receiver detects and records these variations for interpretation

Monitor

Operator makes

multiple passes

over search grid

GPR transmitter/

receiver unit

Trench

Water pipe

1

2

3

4

The GPR transmitter

emits pulses of electromagnetic energy into the subsurface

Objects or disturbances in the soil reflect patterns of energy back to the GPR receiver

Different materials vary in their resistance to the electric field, to return distinct signals

The GPR receiver detects and records these variations for interpretation