NorthStar 961X, Operation And Reference Manual

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Glossary
Page G-2 961 Operations and Reference Manual Rev. D
coordinates
A position defined by either latitude and longitude (see lati-
tude and longitude); TDs (see TDs); or distance and bearing
(see distance and bearing). The positions of lat/lon and TDs are
referred to as absolute, and distance and bearing are relative;
that is, distance and bearing are in relation to a certain refer-
ence point.
corrections Data sent via radio signals to improve the accuracy of GPS
receivers.
cross-track error
(XTE)
The difference between your desired track and your actual
track; that is, how far off you are from your intended course
line.
coverage The extent, ranging from poor to excellent, to which usable
GPS or loran signals encompass a geographical area.
current
The horizontal movement of water caused by tidal or other
forces.
cursor The indicator (that appears on 961 screens as a flashing red
box) in a dialog box or text field, which shows what character
you entered, acknowledge, or edit. Also known as the square
box on the chart screen that, when required, you manually
activate and position.
database A collection of information about waypoints, routes, tracks,
avoidance areas, and charts that’s stored in the 961’s memory.
default A choice the 961 automatically makes in cases where the oper-
ator can’t make an individual selection. The automatic selec-
tion is called the default.
DGPS D ifferential G lobal P ositioning S ystem. The technique of cor-
recting basic GPS position data to increase its accuracy from
100 meters to 1-3 meters.
ephemeris Data that’s used to calculate exact satellite positions, continu-
ally updated and derived from information relayed to the 961
in each satellite’s data stream.
ETA
E stimated T ime of A rrival at the next waypoint, as calculated
by the 961, according to your present SOG and the distance to
the waypoint.