50
Navigator
The push-turn knob fitted to the MALÅ Monitors & Easy locator Controller that acts in a
similar way to a computer mouse allowing the user to navigate menus and update data.
Rotating the knob either allows sequential scrolling through menu options to make a
menu selection or changes selected parameter values. Pressing the knob either executes
the currently selected menu option or sets the value of the selected parameter.
P
Planar reflections
Reflections that appear as horizontal or sub-horizontal lines in GPR profiles. They are
generated from any linear boundary between materials, such as buried stratigraphic and
soil horizons, the water table, and horizontal archaeological features, such as house floors,
as well as pipelines that are parallel to the GPR scan.
Point source reflections
Reflections which often appear as hyperbolas in GPR profiles. They are commonly gen-
erated from distinct, spatially-restricted, non-planar features (‘point targets’), such as rocks,
metal objects, walls, tunnels, voids, and pipes crossed at right angles to the GPR scan.
R
Real Time Kinematic GPS (RTK GPS)
Real Time Kinematic GPS is a highly accurate instrument for positioning, it uses two GPS
receivers (one stationary base and one rover) and a correction signal from the base antenna.
The accuracy is around ± 1-2 cm. Network RTK also available in many locations, where the
correction factor is received via a GSM mobile.
S
Signature
A representation of the reflected radar signal in a GPR profile. Reflected signals are caused by
changes in the dielectric properties of the target medium. These dielectric differences are usual
caused by differences in materials, e.g., a buried object or reinforcing in concrete. Objects of a
discrete length are generally characterized by a hyperbolic reflection in the GPR profile, and are
referred to as point source reflections. A linear object, such as a pipe, will also display the
characteristics of a discrete-length object if the GPR scan is performed perpendicular to its
longitudinal alignment, and are referred to as planar reflections. As the scan is moved towards
the longitudinal alignment of the linear object, the hyperbolic refection flattens until it
approaches a horizontal line in the GPR profile. The shape of the signature is also affected by
many other factors, including the size of the object, the signal velocity, and the object material.
SSD
SSD is an abbreviation for Solid State Drive, which the memory device used for the operating
system and to store data.
Standard GPS
Relatively inexpensive GPS that only uses satellites for positioning, These systems generally
have an accuracy around ± 4 m and are suitable for large scale layer mapping projects