JRC JLR-7700MKII Instruction Manual page 49

JLR-7700 MK 2 GPS Navigator
Terminology
VTD (Speed of the destination component)
VTD (An acronym of "Velocity Toward destination")
This in an index that shows how fast the boat is approaching toward the destination in the unit of knot
when it is navigating at a given bearing angle and speed.
VAR (Speed of the COG component)
VAR (An acronym of "Velocity Along Route")
This in an index that shows how fast the vessel is approaching along the planned route in the unit of knot
when it is navigating at a given course and speed.
CMG (Average bearing)
CMG (An acronym of "Course Made Good")
The bearing angle to the current position when viewed from the starting point.
Starting point
(origin)
48
North
Planned route
c
Current position
CMG
North
VAR
b
a
VTD
V (vessel speed)
VTD = V cos a
VAR = V cos b
CMG = c
Destination