NorthStar 961, Reference Manual

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Glossary
Page G-4 961/962 Operations and Reference Manual, Rev. A
location. All loran stations in one loran chain have the same
GRI. The 961/962 displays GRI next to a pair of Loran-C TDs.
HCRF
H ydrographic C hart R aster F ormat.
heading The compass direction toward which the longitudinal axis of a
vessel points.
HDOP H orizontal D ilution o f P recision.
interference
The electromagnetic interruption of a radio signal that causes
a poor signal reception. Interference may originate from
external sources (such as radio transmitters) or from the vessel
itself (such as alternator noise or precipitation static—see
definition of “P-Static” below).
knot One nautical mile per hour.
latitude
Imaginary lines on the earth's surface running East/West and
expressed in degrees (0-90) north or south of the Equator.
Used in conjunction with the North/South lines of longitude to
determine position.
LCD L iquid C rystal D isplay.
leg
The line, or path, between any two adjacent waypoints in a
route or a trip. Also known as a segment of a route or trip.
leg-up
An orientation of the
CHART
screen in which the viewing
angle matches your desired track when navigating, on a
leg-by-leg basis; leg-up provides a more stable display than
course-up.
longitude
Imaginary lines on the Earth's surface running North/South
and expressed in degrees (0-180) east or west of the Prime
Meridian (a line running from the North to South Pole, passing
through Greenwich, England).
Loran-C
LO ng RA nge N avigation. The Loran-C Radio Navigation
System comprises a series of land-based radio transmitters
emitting precisely timed pulses, which are received and
translated into position fixes by a loran receiver. The 961/962
converts and displays its GPS coordinates into Loran-C
position measurements, or TDs.
loran chain
A group of loran transmitters comprising a master station and
at least two secondary stations.