User's Manual

GPR4 Utility Scanner
User Manual
D
-
000002
-
000023
October
9
,
2019
Copyright © 2019 ESS, LLC. All rights reserved.
Page 16 of 27
f. Velocity of medium The velocity of EM waves is dependent on the material type.
In order to properly convert from time of flight to depth, the velocity of the
medium must selected (see Depth/Time units above). Select the medium type
and the corresponding dielectric constant. The EM velocity is
εν
/c=
where v
is the EM wave velocity, c is the speed of light in a vacuum, and ε is the dielectric
constant of the medium.
Air
ε = 1
Dry soil
ε = 4
Damp soil
ε = 6.5
Moist soil
ε = 9
Wet soil
ε = 16
Saturated soil
ε = 25
g. Distance units Select the units for the horizontal scale on the B-scan
(Centimeters, Inches, Meters, Feet, Seconds).
h. Distance range Select the horizontal range of the B-scan in distance units (10,
20, 50, 100, 200).
The GPR4 Record tab also has buttons for saving the B-scan image and generating
a short report . The image can be saved as a PNG, BMP, or JPG file. The report will
be saved as a PDF file, and will contain the survey metadata and the B-scan image.
7. The Survey Grid tab shows how the linear traverses making up the survey will be
arranged. This step can be skipped when only conducting a single scan line. These
traverses are planned using the button and the dialog shown in Figure 7. To type
into dialog field, click on the field to place the cursor, then press the icon on the
taskbar to bring up the keyboard.
a. Grid type Select either Single line, Parallel lines, or 2D grid (cross hatch). When
conducting pavement surveys, select either Single line or Parallel lines
depending in the width of the area to be scanned.
b. Line directions Select either Same direction or Alternating.
c. Lines in X-axis direction These parameters specify the beginning and ending
coordinates of the lines in the X-direction, and also the distance between them.
d. Lines in Y-axis direction These parameters specify the beginning and ending
coordinates of the lines in the Y-direction, and also the distance between them.
Because lines in the Y-direction are not used for pavement scanning, these fields
can be ignored.
e. Saving the configuration The New, Open, Save, and Delete buttons can be used
to save/recall the dialog settings to/from a named configuration. This is useful
when conducting a series of jobs with a similar layout.