GSSI SIR 4000, Manual

Page: 72 / 163

Geophysical Survey Systems, Inc. SIR® 4000
Manual
MN72-433 Rev F 66
Estimating the Dielectric
By switching the view from the 3D grid to
the 2D profile, you can perform a
hyperbola fitting and get a better estimate
of your Dielectric.
1
Begin collecting a line, but stop
before you reach the end.
2
Back up so that the vertical yellow
line is in the middle of a hyperbola.
3
Change H Cursor to Move and
position the horizontal line at the top
of the hyperbola.
4
Select Dielectric and adjust it until the
hyperbola on the screen matches the
shape of the one in your data.
Step 3: Recollecting or Skipping Lines
If you need to skip or redo a line, use Next Line or Previous Line
to move around the grid. You will see the yellow line move to
indicate your current position. Once the yellow line matches your
current location press the green Start button to collect or recollect
the line.
The new data file will be stored with the proper positioning info
and any old data will be overwritten.
Step 4: Adding a Line Segment
You can collect portions of a line or stop and start collection
along a line by using the Add Segment button. There are two ways to use this button.
Offset the Starting Position:
You can choose
to start away from the baseline if needed.
1
Position the antenna along the line where
you’d like to start.
2
Press Add Segment.
3
Move antenna to the end of the line and
position the center of the antenna over the
opposite baseline from where you started.
4
Press the red Stop button. This will end the
line and shift it to line up with the opposite
baseline.
Note
: The 2D Profile view and Hyperbola
Fitting are only accessible while collecting
Line 1. You can remain in this mode
through the entire 3D collection, but once
you return to the 3D Grid Display, you
cannot access this view again.