AKULA 9000B USER MANUAL
/ SECTION 3
REV:EN05130513-03
Copyright 2006-2015 © Geoscanners AB
19
3.4.1
Scan Box
Scan Range – The scan range box has a field that can be increased or decreased using the up and down arrows
on the right of it. GAS™ automatically recognizes what control unit model is attached to the control PC. Since
GAS™ works with four different kind of ground penetrating radar control units then the available range is restricted
accordingly to the available ones in the connected unit. Please consult your particular unit firmware and technical
specifications for more details on this subject. The range can also be input by typing the desired range in this field.
Scan Rate – The scan rate box has a double purpose, it allows for the selection of the acquisition mode and also
the scan rate while in time mode. The radio buttons at the top permits the selection of one of the three available
acquisition modes:
• Time Mode – In this mode the radar will collect traces based on the specified value of traces per second.
Depending on the selected range and consequently the amount of samples per trace GAS™ will restrict the
maximum amount of traces per second accordingly.
• Distance Mode – In this mode the radar will collect traces only when the survey wheel encoder is sending
information about forward movement of the antenna. The amount of traces per unit length is specified in the
“Wheel Calibration” box as well as the calibration of the survey wheel to guarantee that the unit will collect the
proper amount of traces.
• One Shot Mode – In this mode the radar will collect one trace every time the “one shot” button is pressed or
press enter while in record mode. GAS™ will send the command of acquiring one trace only when the button
has been pressed and released, holding the button down won’t result in the unit acquiring several traces one
after another.
Offset – The electronics in the sampler and transmitter of different antennas have different propagation delays and
therefore the acquired portion of the data might be too late or too early leaving important information outside the
viewing area. The offset moves the viewing portion of the data up or down to give us the right view. As with the
scan range the offset can be modified by using the up and down arrows or by typing in the desired value. Negative
values will move the data up and positive values down. The maximum and minimum offset are depending on the
control unit model number and should be consulted in the technical specifications for the attached unit.
Select Antenna – This drop down box contain all the antenna models supported by the connected control unit.
By selecting one antenna model and pressing “Apply” in the setup panel one loads a factory preconfigured setup
which is suitable for that particular antenna model. In most cases this will be sufficient and no other steps are
required to continue with the survey, but in some cases like heavily conducting soils etc you might need to further
fine tune the parameters to obtain optimal data quality in the given conditions.
