The Global Positioning System (GPS) is a network of satellites that continuously transmit coded information, which makes it possible to precisely identify locations on earth by measuring distances from the satellites. These satellites transmit very low power radio signals allowing anyone with a GPS receiver to determine their location on earth.

The designers originally had a military application in mind...GPS receivers would aid navigation, troop deployment and artillery fire. An executive decree made GPS available for civilian use. The system is free (paid for by tax dollars) and you just need to purchase a GPS receiver!

GPS can be used everywhere unless it is impossible to receive the signals, such as in a low mountain valley, under heavy tree cover, or surrounded by large buildings.
For a detailed description of the Global Positioning System see Uses for GPS. This site describes many of the real-world applications for which GPS is currently being used.

Buying a GPS Receiver

GPS receivers have become a relatively inexpensive hardware purchase as they can be obtained for under $100. More expensive models include features such as an electronic compass, altimeter, or color screen. Some GPS receivers can be connected to wireless phones or laptop computers to take advantage of the features each of those devices already has. For a side-by-side comparison of GPS receiver models, use Google to locate information on the latest models. New models for both handheld GPS and automobile GPS are being released several times a year.

GPS in the Classroom

Using GPS in the classroom is a new and exciting way to enhance geography and science classes. The following web sites highlight various activities that can be completed using GPS.

The Degree Confluence Project is a great way to explore the world. The project hopes to post pictures on their web site of every latitude and longitude integer degree intersection in the world. Here's an example. A similar project could be done throughout your own county. Also worth exploring is this Latitude/Longitude Distance Calculation tool used to determine the distance between two points on the earth given their latitude and longitude.

A popular activity for those who own a GPS is geocaching. Combining hiking and treasure hunting, geocaching involves hiking to a set of coordinates (longitude and latitude) to find a cache; caches are normally left in beautiful locations and contain a log book and an inexpensive item; to trade. Check out official Geocaching site...you probably have a cache near your school! Also explore Geocaching with Kids.

The GLOBE Program has created a Teachers Guide with explanations of GPS and many student activities involving GPS.

Geographic Information Systems

Closely related to GPS is Geographic Information Systems (GIS). GIS uses electronic map layers to explore the relationship between many types of information. The Rocky Mountain Mapping Center's GIS in Educationpage gives teachers a great place to start exploring GIS.

KanGIS also provides information and resources about GPS and GIS. They organize many national projects in which K12 schools collect and share data with classrooms across the country.

Google Earth is a free, downloadable program that allows users to "zoom" to any place on the earth, many of which have satellite photos. Latitude and longitude for each location is displayed.

Geody is a geographic search engine to look for locations on Earth (over 6 millions places), the Moon, Mars, Venus, Mercury, and Space.