While preparing the delivery of a Lagoon 400 that some of you will be able to admire at the international multihull boat show in Lorient from April  18 to 22, 2012, I realized that some  GPS abbreviations can be bewildering!  As a matter of fact, if you have read  some of my latest articles, you certainly know the meaning of COG, VMG or TWA. But what about XTE, DTW, CDI …?

Let’s go for a little summary of common abbreviations on our electronic equipment,: it cannot hurt,  even for the experts!

AWA: Apparent Wind Angle

for more info see here.

AWS: Apparent Wind Speed

for more info see here.

BRG: Bearing to destination

Course toward the next destination point.

BTW: Bearing To Waypoint

Route to the next waypoint.

CDI: Course Deviation Indicator

One of the screens on your GPS allows you to display your boat on a road with two parallel vertical lines: these two lines are called CDI. These lanes identify the track deviation  graphically.

CMG: Course Made Good

Route followed from the start.

COG: Course Over Ground

CTS: Course To Steer

Ideal course to follow to reach the destination.

DPT: Depth

DTG: Distance To Go

Distance from the boat to the arrival destination.

DTW: Distance To Waypoint

Distance to next waypoint.

ETA: Expected Time of Arrival

Estimated time of arrival with SOG constant.

ETE: Estimated Time Enroute

Estimated time to reach the next waypoint selected with SOG constant.


The GOTO function allows you to create a direct route to a point chosen.

GPS: Global Positioning System


Position expressed in latitude and longitude

MOB: Man Over Board

NMEA: National Marine Electronics Association

The NMEA is a standard communication of marine electronic equipment controlled by the National Marine Electronics Association.

POI: Points of Interest

Buoy, port …

POS: Position

SOG: Speed ​​Over Ground

STW: Speed Through Water

Tot TTG: Total Time To Go

Estimate of the total time between the starting point and the ending point.

TWA: True Wind Angle

TWD: True Wind Direction

TWS: True Wind Speed

UT or UTC: Universal Time Coordinated, time at the Greenwich meridian.

VMC: Velocity Made on Course

Efficient speed over ground; for more info see here.

VMG: Velocity Made Good

Efficient speed when nearing the wind direction; for more info see here.

WPT: Waypoint

XTE: Cross Track Error

Distance between  the boat and  the  nearest road point of the direct  course.

If you are looking for the meaning of an abbreviation not listed here, I recommend the site of the U.S. Coast Guard who have a rather comprehensive list.