| Term |
Definition |
Time To First Fix (TTFF) |
If you have not used your GPS unit for several months |
TracBack |
The proprietary Garmin feature which takes your current track log and converts it into a route to guide you back to a starting position. |
Track (TRK) |
Your current direction of travel relative to a ground position (same as Course Over Ground). |
Track log |
Points automatically stored when you are moving. Electronic equivalent of laying down a breadcrumb trail. |
Track Up Orientation |
Fixes the GPS receiver’s map display so the current track heading is at the top of the screen. |
Transducer |
A device |
Triangulation |
A method of determining the location of an unknown point |
TRK |
See Track. |
TRN |
See Turn. |
Troposphere |
The lowest region of the atmosphere between the surface of the earth and the tropopause |
True North |
The direction of the north pole from your current position. Magnetic compasses indicate north differently due to the variation between true north and magnetic north. A GPS receiver can display headings referenced to true north or magnetic north. |
TTFF |
See Time To First Fix. |
Turn (TRN) |
The degrees which must be added to or subtracted from the current heading to reach the course to the intended waypoint. |
Universal Transverse Mercator (UTM) |
A nearly worldwide coordinate projection system using north and east distance measurements from reference point(s). UTM is the primary coordinate system used on U.S. Geological Survey topographic maps. |
Uplink |
A transmission path by which radio or other signals are sent from the ground to an aircraft or a communications satellite. |
USB |
Universal serial bus (pc/usb port on computer). |
User Interface |
The way in which information is exchanged between the GPS receiver and the user. This takes place through the screen display and buttons on the unit. |
User Segment |
The segment of the complete GPS system that includes the GPS receiver and operator. |
UTC |
See Coordinated Universal Time. |
UTM |
See Universal Transverse Mercator. |
Velocity Made Good (VMG) |
The rate of closure to a destination based upon your current speed and course. |
WAAS |
See Wide Area Augmentation System. |
Waterproof |
Most Garmin GPS units are waterproof in accordance with IEC 529 IPX7. IEC 529 is a European system of test specification standards for classifying the degrees of protection provided by the enclosures of electrical equipment. An IPX7 designation means the GPS case can withstand accidental immersion in one meter of water for up to 30 minutes. An IPX8 designation is for continuous underwater use. |
Wavelength |
The distance between points of corresponding phase of two consecutive cycles of a wave. |
Waypoints |
Waypoints are locations or landmarks worth recording and storing in your GPS. These are locations you may later want to return to. They may be check points on a route or significant ground features. (e.g. |
WGS-84 |
World Geodetic System |
Wide Area Augmentation System (WAAS) |
A system of satellites and ground stations that provide GPS signal corrections for better position accuracy. A WAAS-capable receiver can give you a position accuracy of better than three meters |
WiFi |
Wireless networking. |
XTE/XTK |
See Crosstrack Error. |
Y-Code |
The encrypted P-Code. |
