Simrad AUTOPILOT SYSTEM AP50 User Manual
Page 181
Glossary
20221032B
179
SOG - Speed over ground is the actual speed of the vessel
relative to the ocean floor.
True bearing – Bearing relative to true north; compass bearing
corrected for compass error.
True heading – Heading relative to true north.
VDR – Voyage Data Recorder. Recording and storing all
information that can be relevant for reconstructing accidents,
such as time, date, position, speed, heading, depth, video,
communication, etc. Performance requirements are specified in
the IMO A.861(20), the EU directive 1999/35/EC and
IEC61996.
Waypoint - A discrete point, stored in a navigator, located on
the surface of the earth. Normally this point will be identified by
Lat/Lon coordinates although in some systems it may be shown
by T.D.'s.
XTE - Cross Track Error - Used to identify a vessels position
relative to a straight line drawn between two waypoints. The
amount the vessel is off to the left or to the right of this line is
known as the track.