GPS satellites have been freely accessible to the world through the "public good" policy of the United States Air Force and their NAVSTAR Global Position System (GPS.) It is a system of satellites that broadcast a specific radio signal to connect to a receiver like this one. If three or more of the 29 NAVSTAR satellites are in transmission range of the GPS unit, through simple mathematical calculations based on the distances between each orbiting satellite and the receiver, a 3-dimensional position on the X/Y/Z axes is determined. This in turn translates into latitude, longitude and altitude co-ordinates on a GPS receiver. These positions are then represented graphically with points and lines on a GPS unit's screen.
Birders, hikers, and sport spectators have a few things in common; the need for sport optics, their love of outdoor activities and a need to find a location to enjoy it all. Bushnell is accessorizing their line of sport optics with a tool that is usable by everyone, not just outdoorsmen and women, with the NAV500 Portable GPS Vehicle Navigator.
The NAV500 is an all-in-one option for in-car navigation and entertainment. It mounts quickly to a dashboard and not only provides a verbal turn-by-turn set of directions, but with its SD memory card expansion slot, it plays MP3 music and slideshows digital photos.