Global+Positioning+System+(GPS)

= Global Positioning System (GPS) =

toc GPS (Global Positioning System) is a utility funded by U.S. taxpayers and operated by the U.S. Air Force. The system has been operational since 1995, and provides worldwide public access to positioning, navigation, and timing services. While the U.S. military operates it, legislation has been passed to ensure the government does not interfere with its services to the public. GPS allows for people to obtain almost exact location details, from latitude and longitude to elevation.

Until 2000, civilians using GPS systems did not receive as accurate information as they do now. This was the product of “Selective Availability,” which was implemented by the U.S. government under reasons of national security. Legislation in 2000, however, mandated that “SA” would no longer be used, and now with “augmentation systems” it is possible to come within 10-15 centimeters of a precise location.

The GPS functions through the use of satellites that transmit one-way radio signals. The signals consist of the location and time relative to the satellite. All of the operating satellites are coordinated to emit their signal at the same time. Any receiver, such as a smartphone, uses several of these signals to pinpoint its location. The receiver calculates this by factoring in the amount of time it takes for the signals from each satellite it is referencing to reach the receiver. A receiver must detect 3 to 4 satellite signals (4 if altitude is to be determined) in order to make the calculations to determine its location. There are now 27 satellites in operation to ensure constant availability for users, along with several other inactive ones orbiting to serve as backup. media type="youtube" key="wi_3XwkA8cQ" height="315" width="420"

GPS as a Web Resource
media type="custom" key="11287676" align="left" GPS has now been widely integrated into web-based services. A popular use of the service comes through smartphones. Besides its basic utility as a location tracker, it has been implemented to further recreational activity through the game of Geocaching. Applications are available for smartphones so that players can use their phone to locate a hidden “treasure.”

Another fun yet practical capability GPS offers is the ability for users to track their coordinates via a receiver (such as a smartphone) and then upload those coordinates into web-based programs such as GPSVisualizer. This online resource combines user-defined coordinates with other web-based applications such as Google Maps to generate personalized maps. From this, users can visually plot where they have been.

Other Uses and Possibilities
Beyond the direct application of tracking the time and location, GPS offers many tangential possibilities. As web-technologies continue to develop, people will undoubtedly come to recognize further ways to integrate the location-based services of GPS into their daily lives for work and play. For instance, augmented reality applications on smartphones integrate location-based data to provide more detailed descriptions of sites surrounding the smartphone user. Museums could even apply geocaching principles to their collections so visitors could go on a “hunt-and-seek” for the highlights of the museum.

One such example of GPS being applied towards historical education is the iPhone application called //WolfWalk.// This application allows users to learn about points of interest around the campus of North Carolina State University: @http://www.lib.ncsu.edu/wolfwalk/

**References**
Brain, M., & Harris, T. (n.d.). How GPS receivers work. Retrieved November 7, 2011, from @http://electronics.howstuffworks.com/gadgets/travel/gps.htm

Galaxyexplorers. (2006, December 31). Global Positioning System [Video file]. Retrieved November 13, 2011, from @http://www.youtube.com/watch?v=wi_3XwkA8cQ

//Geocaching – The Official Global GPS Cache Hunt Site//. (2011). Retrieved September 25, 2011, from @http://www.geocaching.com/

GPS.gov. (2011, August 26). GPS.gov: GPS Overview. Retrieved September 25, 2011, from @http://www.gps.gov/

GPS.gov. (2011, August 26). GPS.gov: Augmentation Systems. Retrieved September 25, 2011, from @http://www.gps.gov/systems/augmentations/

Miaow, M. (2004, November). Geocache CZ 02 [Photograph]. Retrieved November 13, 2011, from @http://commons.wikimedia.org/wiki/File%3AGeocache_CZ_02.JPG

//GPSVisualizer.com//. (2011). [Home Page]. Retrieved September 27, 2011, from @http://www.gpsvisualizer.com/

Smithsonian. (n.d.). How Does GPS Work? Retrieved September 25, 2011, from @http://www.nasm.si.edu/gps/work.html

//Wolfwalk.// (n.d.). Retrieved November 17, 2011, from @http://www.lib.ncsu.edu/wolfwalk/