Raytheon RayChart 620 Operation Manual page 114

Glossary
NMEA
SOG
TD
TTG
VMG
WPT
XTE
National Marine Electronics Association (interconnection
standard)
Speed Over Ground. A calculation of the rate of movement
of the vessel over the ground.
Time Difference. The difference in time of arrival
(measured in microseconds) of the two Loran signals, one
from the master transmitting station and the other from the
secondary.
Time To Go
Velocity Made Good. The component towards your
destination based on your vessel's current speed.
Waypoint
Cross Track Error
101