AKULA 9000B USER MANUAL
/ SECTION 4
REV:EN05130513-03
Copyright 2006-2015 © Geoscanners AB
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The signal position or offset is extremely important
to be set correctly, the algorithm to calculate
the relative dielectric permittivity assumes that
the signal propagates always through the media
and that a constant RDP is present. This latest
assumption is not always true, but we need to
get to this approximation as close as possible
otherwise the results of the hyperbola fitting tool
are meaningless.
Once you have set up your radar correctly and
are in record mode, move your antenna forward
until you identify a full hyperbola. Please drive the
antenna a little bit further so you can center your
hyperbola on the screen, this will provide the best
results when trying to fit the calculated hyperbola.
Two hyperbolas: a plastic sewage pipe and a metal
water pipe embedded in the concrete floor
The hyperbola tool is now started and ready to use.
The calculated hyperbola now it is fitted to the real one.
In this example we have found two hyperbolas,
the first one from the left is a sewage plastic pipe
buried in the ground in a basement at 40cm below
the surface according to the drawings of the house.
The second hyperbola is a shallow metal water pipe
embedded in the concrete slab of the floor. The
bottom of the concrete slab bottom is clearly seen
in the b-scan area.
Press the hyperbola fitting tool button to start the
tool. A red line showing us where the antenna is at
the moment with a calculated hyperbola on it and
four buttons will appear in the b-scan area.
Move your antenna back and you’ll see that the red
line will also move backwards and show the current
position. Try to put the red line with the calculated
hyperbola exactly in the middle of the hyperbola on
the screen. When you have done that adjust the
vertical position of the calculated red hyperbola so
it fits the real hyperbola on the data.
This adjustment can be done by pressing the up
or down buttons that you see on the screen or
alternatively by pressing up or down arrows on
your keyboard. When the vertical position of the
hyperbola has been established adjust then the
width of the hyperbola with the left or right arrow
buttons on your screen or the left or arrow buttons
on your keyboard. Pressing the left arrow will cause
the hyperbola to broaden and pressing the right
arrow will have the opposite effect.
