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Appendix F
Navigation Terms
Odometer— A running tally of distance travelled, based upon the distance between second-by-second
position readings.
Off Course— The distance you are off a desired course in either direction, left or right. Also referred
to as ‘cross-track error’ or ‘course error’.
Speed— The current velocity at which you are travelling, relative to a ground position. Also referred
to as ‘ground speed’.
Time To— The estimated time required to reach a GOTO destination, or the next waypoint in a route.
Also referred to as ‘estimated time en route’.
Time to Destination— The estimated time required to reach a GOTO destination, or the fi nal
waypoint in a route.
Time to Next— The estimated time required to reach a GOTO destination, or the next waypoint
in a route.
To Course— The recommended direction to steer in order to reduce course error or stay on course.
Provides the most effi cient heading to get back to the desired course and proceed along your route.
Track— The direction of movement relative to a ground position. Also referred to as ‘ground track’.
Trip Odometer— A running tally of distance travelled since last reset. Also see ‘Odometer’.
Total Average Speed— Average speed of unit for both moving and stopped speeds since last timer
reset.
Total Trip Timer— Total time the unit has been in operation since last reset of the trip timers.
Turn— The angle difference between the bearing to your destination and your current track. ‘L’
indicates you should turn left, ‘R’ indicates you should turn right. The degrees indicate the angle
you are off course.
VMG— Velocity Made Good. The speed you are closing in on a destination along a desired course. Also
referred to as the ‘vector velocity’ to your destination.
DESIRED
TRACK
NORTH
'FROM'
WAYPOINT
NORTH
BRG
TRK
DESTINATION
WAYPOINT
OFF COURSE
SPEED
DISTANCE TO DESTINATION
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