ATLAS North America Proprietary
Sea Scan® ARC Explorer™ Manual
1 of 1
Page: 59
Issue: 4.2.1
2SFT1-0001
Manual
layback (LB)
The surface distance between the navigation antenna and
the towfish
longitude
The angular distance east or west of the prime meridian
that stretches from the North Pole to the South Pole and
passes through Greenwich, England
lossy medium
The physical degradation of an acoustic signal as a result of
such conditions as absorption by the water, wave-front
spreading, or scattering
LUT
Look-Up Table
magnetometer
An external device that measures the current total magnetic
field
marker
An item of interest the operator can tag in the sonar
window; the item might be a feature on the bottom or an
item of interest
MB
MegaByte (1,000,000 Bytes)
MRU
Most Recently Used
nadir
A point along the swath that is directly beneath the
towfish; a location in the acoustic pulse
NMEA
The National Marine Electronics Association
NMEA Protocol 0183
A standardized protocol that allows marine instruments to
transmit and receive depth information. This
communication is based on a block transmission or groups
of NMEA 0183 sentences, which are transmitted over the
serial cable. Each sentence has a header that uniquely
identifies the source of the data and the information
contained in the data string.
NOAA
National Oceanographic and Atmospheric Administration
noise
Extraneous acoustic sound or electrical waveforms that
interfere with the sonar signal
null point
The location of the antenna of the external navigation
device
OTG
Over The Ground
overlap
The bottom area covered more than once as the towfish
travels a predetermined pattern or grid
PC
Personal Computer
ping
A single pulse of a sonar system
Plotter
A software module that shows track position and swath
coverage
