NorthStar MX500 Operator's & Installation Manual page 264

Operator's Manual
GMT
GPS LOG
GPS SYSTEM TIME
GREAT CIRCLE NAVIGATION
HDOP (Horizontal Dilution of Precision)
HEADING
HEADING-TO-STEER
HEALTH
250
Greenwich Mean Time. See also UNIVERSAL TIME COORDI-
NATED.
A feature of the navigator that measures the sailed distance based
on the GPS signals rather than a water distance sensor.
Time corrected to Universal Time Coordinated (UTC) and used as
the time standard by the user segment of the GPS system.
Navigation based on a Great Circle calculation. The advantage of
Great Circle navigation is that it brings you the shortest way through
the active route. The disadvantage is that a Great Circle track may
differ from the straight rhumb line that is easily drawn on a Mercator
projected chart. Great Circle navigation is recommended for ocean
voyages only. The advantage increases by higher latitude (north
or south).
An indicator of the two dimensional accuracy in position (latitude
and longitude). See DILUTION OF PRECISION.
The direction in which the vessel is pointed, expressed as angular
distance from north clockwise through 360 degrees. HEADING
should not be confused with COURSE. The HEADING is con-
stantly changing as the vessel yaws back and forth across the
course due to the effects of sea, wind, and steering error.
The angle of track required to steer the vessel or vehicle from its
present position to its planned destination point. This angle dif-
fers from heading, which is its present angle of track with respect to
true north.
See SATELLITE HEALTH.
Glossary
Version 3.0