GSSI SIR 30, Manual

Page: 150 / 150

Geophysical Survey Systems, Inc. SIR® 30
Manual
MN 93-101 Rev E 144
Nano-second:
unit of measurement for recording the time delay between transmission of a radar pulse
and reception of that pulse’s reflections. Equal to one one-billionth of a second.
Noise:
unwanted background interference that can obscure true data.
Noise floor:
the noise floor is a measure of the summation of all the noise sources and unwanted signals
generated within the data acquisition and signal processing system.
nS:
see Nano-Second.
Oscilloscope:
device used to view and measure the strength and shape of energy waves. Common term
in GPR industry for a method of data display showing actual radar wave anatomy.
Range:
the total length of time (in nanoseconds) for which the control unit will record reflections. Note:
indicates two-way travel time.
RF:
Acronym for radio frequency.
Sample:
a radar data point with two attributes: time and reflection amplitude. A third attribute, position,
is assigned by the user. Under-sampling will produce a scan wave that does not contain enough
information to draw a smooth curve. It may miss features. Over-sampling will produce a larger data file.
Samples/Scan:
the number of samples recorded from an individual radar scan. Commonly set to 512.
Scan:
one complete reflected wave from transmission to reception, sometimes called a trace.
Survey wheel:
wheel attached to an antenna and calibrated to record precise distances. Necessary for
accurate data collection.
Time-slice:
a horizontal plan view of amplitude values drawn from adjacent vertical profiles. The time-
slice is produced for a particular time-depth and is vital for understanding the horizontal positions of
features in a survey area.
Time window:
the amount of time, in nanoseconds, that the control unit will count reflections from a
particular pulse. Set by the operator.
Transect:
a line of survey data. An area is systematically surveyed by recording transects of data at a
constant interval. The transects are then placed in their correct position relative to each other in a
computer and horizontal time-slices are produced.
UWB:
Acronym for Ultra-Wide Band. Refers to the wide frequency band of emissions put out by a GPR
device.
Wiggle trace:
method of GPR data display showing oscilloscope trace scans placed next to each other to
form a profile view. Commonly used method in seismic studies.