101
Bearing (BRG): Bearing is the direction to a destination waypoint measured in degrees
from North (i.e. 321°, where 000° is North, 090° East, 180° is South, 270° is West).
Chartplotter: Chartplotter describes a navigation device that shows Present Position
on a Map, along with Tracks, Waypoints, and Routes. All Chartplotters are also
considered Trackplotters. All Humminbird® GPS Combo units are Chartplotters. See
Trackplotter.
Cold Start: Cold Start refers to the procedure that a GPS receiver must perform when
it does not have historical information regarding its current location. This procedure
typically lasts for several minutes, and may be experienced upon first power up of
the receiver, or if the receiver has been moved a great distance.
Course Over Ground (COG): Course Over Ground is the current direction the boat is
traveling measured in degrees from North (i.e. 321°, where 000° is North, 090° East,
180° is South, 270° is West). When the Course Over Ground is equal to Bearing, the
boat is said to be “On Course” and will arrive at the destination in the most efficient
manner. COG is often confused with Heading. See Heading.
Cross Track Error (XTE): Cross Track Error is the straight-line distance of the boat from
the intended Track. XTE measures how far the boat is off course, and also triggers the
Off Course Alarm. See Track.
Differential GPS (DGPS): Differential GPS is a system to improve the position
accuracy of the Department of Defense GPS through the use of secondary
“correction signals” broadcast from ground stations around the coastal United
States and on some inland waterways. These correction signals are provided by the
USCG and received by an auxiliary Differential Beacon Receiver (DBR) that connects
to the GPS receiver. The advent of WAAS has largely negated the need for the added
expense of a DBR in the United States.
Distance To Go: Distance To Go is the straight-line distance between Present
Position and the Destination Waypoint. DTG and SOG (Speed Over Ground) are used
to calculate Time To Go. See Time to Go and Speed Over Ground.
Estimated Position Error (EPE): Estimated Position Error is a calculation that indicates
the potential position inaccuracy the user may experience due to a variety of GPS factors
which include satellite position in the sky, signal strength and others factors.
