| Term |
Definition |
Data card |
Card that stores mapping software. |
Datum |
A math model which depicts a part of the surface of the earth. Latitude and longitude lines on a paper map are referenced to a specific map datum. The map datum selected on a GPS receiver needs to match the datum listed on the corresponding paper map in order for position readings to match. |
DCG® |
See Depth Controlled Gain. |
Depth Controlled Gain (DCG) |
A Garmin proprietary technology that automatically adjusts fishfinder sensitivity according to depth |
Desired Track (DTK) |
The compass course between the "from" and "to" waypoints. |
DGPS |
See Differential GPS. |
Differential GPS (DGPS) |
An extension of the GPS system that uses land-based radio beacons to transmit position corrections to GPS receivers. DGPS reduces the effect of selective availability |
Dilution Of Precision (DOP) |
A measure of the GPS receiver/satellite geometry. A low DOP value indicates better relative geometry and higher corresponding accuracy. The DOP indicators are GDOP (geometric DOP) |
Distance |
The length (in feet |
DOD |
The United States Department of Defense. The DOD manages and controls the Global Positioning System. |
DOP |
See Dilution Of Precision. |
Downlink |
A transmission path for the communication of signals and data from a communications satellite or other space vehicle to the earth. |
DTK |
See Desired Track. |
Elevation |
The distance above or below mean sea level. |
Ellipsoid |
A geometric surface |
EPE |
See Estimated Position Error. |
Ephemeris Data |
Current satellite position and timing information transmitted as part of the satellite data message. A set of ephemeris data is valid for several hours. |
Estimated Position Error (EPE) |
A measurement of horizontal position error in feet or meters based upon a variety of factors including DOP and satellite signal quality. |
Estimated Time Enroute (ETE) |
The time it will take to reach your destination (in hours/minutes or minutes/seconds) based upon your present position |
Estimated Time Of Arrival (ETA) |
The estimated time you will arrive at a destination. |
ETA |
See Estimated Time Of Arrival. |
ETE |
See Estimated Time Enroute. |
Frequency |
The number of repetitions per unit time of a complete waveform |
