A global positioning system (GPS) contains 24 Department of Defense GPS satellites that are used for location and navigation purposes. The receiver processes the distance between the receiver and four GPS satellites all together to establish the receiver’s precise geographic location. These receivers are exact within 3 meters, give or take. These receivers are used by persons to figure out their geographic location while hiking or to obtain driving directions. GPS technology is also used to locate and dispatch police cars, ambulance, and other emergency vehicles. One recent worry is the likelihood that the older GPS satellites might not work, before new ones can be launched. A current General Accountability Office (GAO) report established that there is an 80% chance that a full GPS service will be operational until 2014. Right now, there are 30 GPS satellites in orbit.
The Widespread Use of GPS Navigation
The GPS(or Defense Navigation Satellite System as it was first called) was created in 1973 by the United States Department of Defense and was exclusively used by the US military for their own personal needs. Civilian use of the GPS became available in 1994 but had limited accuracy(about 100m) while the military still held on to the highest quality signal. Over the years as technology evolved, so did the accuracy of the GPS and now days it is accurate to within 3 meters. On May 2nd, 2000, the "Selective Availability" was discontinued and civilians were allowed use of the highest quality GPS signals which started the whole navigation craze. Now GPS can be found standard in most cars and cell phones and the accuracy of the GPS is constantly improving as technology evolves.
Specific information was obtained from http://en.wikipedia.org/wiki/Gps
Types of GPS Receivers
- Handheld GPS Receivers
- These devices are commonly used by individuals to determine their geographic location while hiking. Other uses for handheld devices might be used on the job by land surveyors, farmers, or fisherman.
- Car-Mounted GPS Receivers
- Car Mounted GPS Receivers are most commonly used today among civilians to help people navigate directions while driving. While car mounted GPS receivers can be purchased separately to be used with any car, almost all vehicles today offer an upgrade to include a GPS built into a car.
- GPS Receivers Integrated into Mobile Phones
- Another option becoming more popular every day for directions while traveling are now being used via mobile phones. A lot of mobile phone include free GPS with their data plan while others can purchase it additionally. This allows easy access to a GPS at any time with out having to purchase an additional unit.