User's Manual

www.malags.com
8
SOIL LAYERS
BOULDER
Distance
D
e
p
t
h
SURFACE
Figure 2.2 An example of a continuous record of radar traces.
2.2 Basic information in investigation depths and
velocities
The problem of range (depth) vs. resolution is well known for
the type of investigations that GPR represents. Sufficient
penetration depth may be achieved but it may require a low
frequency that reduces the resolution. Range is defined as the
distance at which a target can be detected. Resolution on the
other hand is defined as the smallest size an object or thinnest
layer that may be detected. There often is a compromise
regarding the choice of antenna frequency for a particular
application at a specific site.
The depth penetration with different frequency antennas varies
greatly depending on local soil conditions. Primarily the
depth/resolution requirements and the soil conditions at the
site determine the choice of antenna frequency. The table
below is hoped to be of assistance when selecting antenna
frequency based on the depth interval of interest.