Humminbird 161 - Manual (Page 105)

98
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.
Fix Type: Fix Type indicates whether the GPS receiver is providing 2D fix or 3D fix. A
2D fix requires only three satellites and provides only latitude and longitude. A 3D fix
requires four or more satellites, and provides latitude, longitude and altitude.