NorthStar Navigation EXPLORER 657 operation manual Navigation data

Navigation data

The boat is sailing from the start to the destination and has moved off the plotted course from the start to the destination.

BRG	Bearing to Destination: Bearing to the destination from the boat.
BRG	Bearing to cursor: Bearing to cursor from boat (cursor mode, see section 3-2-1 [note the -1 added
	there])
CDI	Course Deviation Indicator: When the boat is navigating to a point, the chart and highway
	windows show a parallel line on either side of the plotted course. These two lines are called the
	Course Deviation Indicator (CDI) lines. The distance from the plotted course to a CDI line is the
	CDI scale.
	Set the CDI scale (see section 17-2) to the maximum distance that the boat should deviate from
	the plotted course. The chart and highway windows show the CDI lines, which are like a highway
	over the water where the boat will move. The windows show how far the boat has deviated from
	the plotted course and if the boat is approaching a CDI line. If the XTE alarm is enabled (see
	section 17-9) an alarm will sound if the boat reaches a CDI line.
COG	Course Over Ground: Direction in which the boat is moving over the ground.
CTS	Course To Steer: Optimum course to steer to return to the plotted course.
DTG	Distance To Go: Distance from the boat to the destination.
ETA	Expected Time of Arrival: At the destination, assuming that SOG and COG remain constant.
DST	Distance from boat to cursor (cursor mode, see section 3-2)
SOG	Speed Over Ground: Current boat speed over the ground. This is not necessarily the same as
	the boat speed through the water nor the speed at which it is approaching the destination.
STR	Steering: The difference between COG and CTS.
TTG	Time To Go: The estimated time to reach the destination.
XTE	Cross Track Error: The distance from the boat to the nearest point of the plotted course. XTE
	may have a letter: R means steer to the right to return to the plotted course, L means steer to
	the left.
VMG	Velocity Made Good: The speed at which the boat is approaching the destination.

Destination

DTG (distance)

SOG (speed) VMG (speed)

BRG

STR COG

CTS

Destination
Plotted	XTE
course
	(distance)
	Boat
ne	position
li
I
CD
CDI scale	CDI scale

ne li

I CD

Plotted course

Start

Boat position

(distance)	(distance)
Start

Northstar Explorer 657 Installation and Operation Manual 91