Noggin 1000 Smart Cart, Руководство пользователя

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Smart Systems User’s Manual Version 1.1
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It is important to remember that just because the Depth setting is set to a certain
value, it does not necessarily mean that the Noggin is able to penetrate to that
depth and collect data. For example, if the Depth setting is 5 metres but the
material penetration is only 3 metres the last 2 metres of the image will not
contain subsurface information. Some materials will absorb the Noggin signal and
limit penetration to less than the selected depth.
If the depth setting is deeper than the Noggin signals penetrate, the data in the lower
part of the data screen will look blank or speckled rather than signal with continuity.
Velocity
The wave velocity depends on the properties of the material. The Noggin
plus
software
allows the user to input a velocity, which changes the total time window collected by the
system.
See Section 6.2.8 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.
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
If units are metres then velocities will appear in metres per nanosecond (m/ns). If units
are feet then velocities will appear in feet per nanosecond (ft/ns). To change units see
Section 6.3.1 – Depth Units.
The Noggin will accept units in metres/nanosecond or feet/nanosecond depending on
the Depth Units setting.
Depth Units
This is the setting for the units of the horizontal depth lines that appear on the screen.
The available settings are metres, feet or nanoseconds (ns). If nanoseconds are
selected the “depth” lines (see Section 6.2.2) are actually time lines.
1. metres
2. feet
3. nanoseconds