GSSI SIR 30, Manual

Page: 79 / 150

Geophysical Survey Systems, Inc. SIR® 30
Manual
MN 93-101 Rev E 73
Note:
All SIR 30 horn default settings use a 10 MHz IIR HP filter by default. When using the 4105
NR and the 41000 and 42000S select FIR FILTERS and turn on CUSTOM FILTER. When the
CUSTOM filters are ON, all other Vertical IIR and FIR filters with the exception of the IIR HP are
disabled.
4
Select SIGNAL PROCESS > FIR FILTERS.
The FIR filters are OFF by default. If the User wishes to use FIR filters, the User should enter the
desired Low Pass (LP) and High Pass (HP) filter values, then select the IIR High Pass and Low Pass
filters and turn them off.
5
For the 4105 select
:
FIR High Pass = 250 MHz, FIR Low Pass = 5000 MHz, IIR High Pass = 100 MHz.
6
For the 4108 select
:
FIR High Pass = 250 MHz, FIR Low Pass = 3000 MHz, IIR High Pass = 100 MHz.
7
Select SIGNAL PROCESS > GAIN. If the User has selected a Horn center frequency for the
antenna(s) in the Antenna Type(s) in the System Settings menu, the default setup will have one (1)
gain point. The Auto Gain is ON by default. If the User has deployed more than one antenna, the User
must select the active channel to make any acquisition changes to that specific channel.
Note:
The User should not change the default number of gain points when using the Horn antennas.
Note:
When deploying more than one (1) antenna, the User should select the active channel number
before making any changes to acquisition parameters.
Step 4: The Metal Plate Calibration File
Prior to beginning any road or pavement thickness survey, the User must collect a Metal Plate Calibration
file. RADAN-7 requires this calibration file in order to generate accurate GPR transmission velocities of
the pavement and to correct for ‘antenna bounce’ during data collection.
1
Select RADAR CONFIG > RADAR.
2
Set the RUN MODE to TIME.
3
Center the metal plate under the horn antenna. You will note the strong metal plate reflection at the
surface.
4
Click the INIT button to reset the gain. The Auto gain will reduce the gain and the metal plate ground
surface reflection amplitude will decrease.
5
Select START SCAN. The system will begin to collect data.
6
Have an assistant begin to jump up and down on the bumper at the end of the vehicle where the where
the antenna is attached. The User should collect approximately 10 seconds of data. The antenna direct
coupling is highlighted in
dark blue and the surface\metal plate reflection is highlighted in red .