User's Manual

Smart Systems User’s Manual Version 1.1
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5.8 Advanced Topics
5.8.1 How Depth is Determined
Ground penetrating radar systems record the time for a radio wave to travel to a target
and back. The depth to that target is calculated based on the velocity at which the wave
travels to the target and back. It is calculated as:
D = V x T/2
Where D is Depth (m)
V is Velocity (m/ns)
T is Two-way travel time (ns)
The wave velocity depends on the properties of the material. The Noggin software
allows the user to input different velocities, which changes the total depth range
displayed on the screen. The velocities of common materials are:
Material Velocity (m/ns) (ft/ns)
Air 0.3 1
Ice 0.17 0.57
Dry Soil 0.15 0.5
Dry Rock 0.12 0.4
Soil 0.1 0.33
Wet Rock 0.1 0.33
Concrete 0.1 0.33
Pavement 0.1 0.33
Wet Soil 0.065 0.22
Water 0.033 0.11