About GPS
The Global Positioning System (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit by the U.S. Department of Defense. GPS was originally intended for military applications, but in the 1980s, the government made the system available for civilian use. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or setup charges to use GPS.

GPS satellites circle the earth twice a day in a very precise orbit and transmit signal information to earth. GPS receivers take this information and use triangulation to calculate the user's exact location. Essentially, the GPS receiver compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. Now, with distance measurements from a few more satellites, the receiver can determine the user's position and display it on the unit's electronic map.

A GPS receiver must be locked on to the signal of at least three satellites to calculate a 2D position (latitude and longitude) and track movement. With four or more satellites in view, the receiver can determine the user's 3D position (latitude, longitude and altitude). Once the user's position has been determined, the GPS unit can calculate other information, such as speed, bearing, track, trip distance, distance to destination, sunrise and sunset time and more.

Today's GPS receivers are extremely accurate, thanks to their parallel multi-channel design. Garmin's 12 parallel channel receivers are quick to lock onto satellites when first turned on and they maintain strong locks, even in dense foliage or urban settings with tall buildings. Certain atmospheric factors and other sources of error can affect the accuracy of GPS receivers. Garmin� GPS receivers are accurate to within 15 meters on average.

The eTrex Vista combines a basemap, with a barometric altimeter and electronic compass. The compass provides bearing information while you're standing still and the altimeter determines your precise altitude. The Vista is also designed to provide precise GPS positioning using correction data obtained from the Wide Area Augmentation System (WAAS). This product will provide position accuracy to less than three meters when receiving WAAS corrections.

Specification:
* Receiver : 12 channel. * Number of Waypoints: 1,000 * Built in Memory: 24 MB * # of Routes / # of waypoints per route: 20/125 * Database or Basemap: Americas Highway or Atlantic Highway or Pacific Highwayand Marine Point Database / Additional map options MapSource CD-ROM uploadable information * Battery Life: 12 HR (2 AA) * Display Size: (H x W in inches) 2.1 x 1.1 * Display type: 4 level Gray LCD * Area Calculation * Pixels (H x W): 288 x 160 * Built in Standard GPS Antenna * TracBack Mode * # of Tracklog Points 10,000 * Waterproof Standard : IPX7 * Unit Size: (H x W x D in inches) 4.4 x 2.0 x 1.2 * Thumb Stick (5-position cursor switch) * Map Storage Internal Memory * Single level Backlit Display * WAAS/EGNOS capability * Loran TD position format * MGRS position format * Glide Ratio, Glide Ratio to Destination, and Vertical Speed to Destination * Built-In Electronic Compass * Built-In Barometric Altimeter * Hunting / Fishing calculator * Celestial Information Page * Built in calendar * Voltage Range 2.5 * Waypoint Icons