AKULA 9000B USER MANUAL
/ SECTION 4
REV:EN05130513-03
Copyright 2006-2015 © Geoscanners AB
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4.5
Record Mode in One Shot Mode
In geological or archeological applications sometimes it is necessary to make surveys in specific locations or points
if you prefer. For this kind of surveys we have implemented the one shot mode which basically will collect one trace
at the time when you press the one shot button. This is also particularly useful when doing common mode point
measurements to find out the dielectric constant of the material under investigation.
To enter one shot mode select the corresponding radio button in the “scan rate” section of the “scan box” settings.
Enter record mode by pressing the record mode button or pressing Ctrl+D on your keyboard. While in record mode
press the “start record” button or Ctrl+R on your keyboard. Exactly the same like in distance mode no data will
start filling up the b-scan area on the screen. This is because the radar is in stand by and will not start collecting
one trace until you press the “one shot” button or press Enter on your keyboard. Pressing the space bar on your
keyboard will also make the radar collect one trace, but it will also add a marker to it. Pressing the marker button
in the main toolbar will have the same effect.
Stop collecting the data and exit by pressing the “stop record” button or by pressing Ctrl+S on your keyboard. As
with all other modes the control software will ask about saving the data if the automatic saving check box in the
general settings was left unchecked.
4.6
Hyperbola Fitting Tool
The depth to the target buried in the material is depending on the relative dielectric permittivity of the material.
The better and more accurately we know this parameter the better and more accurately we can find out the depth
to the target. There are several tools available to find out the relative dielectric permittivity, GAS™ has two of them
in the standard tool set: hyperbola fitting and calibration depth.
The hyperbola fitting tool is best suited for cylindrical targets like pipes or narrow fractures that will produce a
hyperbola like reflection in the data. You need to have the radar operating in distance mode to be able to use
this tool since all the measurements are based on plain geometry. Another point to think about when using the
hyperbola fitting tool is that the signal position has to be set correctly. That means no air wave or at least as little
as we can get.
Incorrect
signal position or offset
Correct
signal position or offset
