Sensors & Software Noggin 100, User Manual

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Noggin 13-Survey & Map Mode
95
13.3.1.2 Velocity
The wave velocity depends on the properties of the material. The Noggin software allows the
user to input a velocity, which changes the total time window collected by the system.
See 13.2.10: p.88 for a discussion about determining velocity.
A table of typical radar velocities in various materials is given below. If in doubt, use a value of
0.10 m/ns. This is a good average velocity that will provide a good estimate of depth in most
situations.
If units are meters then velocities will appear in meters per nanosecond (m/ns). If units are feet
then velocities will appear in feet per nanosecond (ft/ns). To change Depth Units see
13.3.1.3:
p.95 .
The Noggin will accept units in meters/nanosecond or feet/nanosecond depending on the Depth
Units setting.
13.3.1.3 Depth Units
This is the setting for the units of the horizontal depth lines that appear on the screen. The
available settings are meters, feet or nanoseconds (ns).
1) meters
2) feet
3) nanoseconds
If nanoseconds are selected the “depth” lines ( 13.2.2: p.79 ) are actually time lines.
Material Velocity (m/ns) (ft/ns)
Air 0.300 1.000
Ice 0.170 0.558
Dry Soil 0.130 0.427
Dry Rock 0.120 0.394
Soil 0.100 0.328
Wet Rock 0.100 0.328
Concrete 0.100 0.328
Pavement 0.100 0.328
Wet Soil 0.065 0.213
Water 0.033 0.108