Dead Reckoning
A capability that allows you to get navigation guidance even when GPS signals are obscured, for example in tunnels or around tall buildings. Also know as assisted satellite navigation by TomTom.
DGPS - Differential Global Positioning System
A method of improving the accuracy of your receiver by adding a local reference station to augment the information available from the satellites. It also improves the integrity of the whole GPS system by identifying certain errors.
EGNOS - European Geostationary Navigation Overlay Service
GPS - Global Positioning System
A network of at least 24 satellites orbiting the earth that continuously transmits data, which provide precise, positioning, navigation information anywhere on earth. It is used for routing, tracking and identifying locations. It is also known as the NAVSTAR system.
MSAS - Multi-Functional Satellite Augmentation System
Multi-Destination Routing
Multi-destination routing lets you specify several locations you want to visit and then creates a single route that passes through all of them. Better GPS systems should be able to adjust the order of destinations to create a more efficient route. This feature is particularly useful for pickup/delivery drivers and real estate agents, who often need to visit several locations in a single trip.
NAVSTAR - NAVigation Satellite Timing and Ranging
The official U.S. Department of Defense name for GPS.
NavTeq and Tele Atlas
Both are companies that provide street-level mapping data to GPS manufacturers. Garmin and Magellan utilize the NavTech maps. TomTom, on the other hand, uses the TeleAtlas maps.
PND - Personal or Portable Navigation Device
POI - Points Of Interest
TFT - Thin Film Transistor
A type of LCD that is sometimes called an active matrix. TFT is actually a component of a an LCD to improve the quality and control of the LCD display. It is basically a tiny transistor linked to each individual pixel on the screen. Some touch-screen GPS units utilize TFT technology.
TTS - Text To Speech
WAAS - Wide Area Augmentation System
a system of satellites and ground stations that provide GPS signal corrections, giving you even better position accuracy. How much better? Try an average of up to five times better. A WAAS-capable receiver can give you a position accuracy of better than three meters 95 percent of the time. And you don't have to purchase additional receiving equipment or pay service fees to utilize WAAS.
WAAS enabled GPS represents the next generation of GPS accuracy, providing several meters of precision accuracy even in altitude.
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., camp, the truck, a fork in a trail, or a
favorite fishing spot). Waypoints may be defined and stored in
the unit manually by taking coordinates for the waypoint from a
map or other reference. This can be done before ever leaving
home. Or more usually, waypoints may be entered directly by
taking a reading with the unit at the location itself, giving it
a name, and then saving the point. Waypoints may also be put
into the unit by referencing another waypoint already stored,
giving the reference waypoint, and entering the distance and
compass bearing to the new waypoint.