Global Positioning Systems

Global Positioning Systems (GPS)

GPS was developed by the Department of Defense and its specific use was originally intended for the military but during the 1980's it became available to the public. GPS has several key applications: navigation, tracking, mapping and timing.

GPS is a system involving a geospatial reference point located on Earth and approximately 24 satellites orbiting Earth two times a day, which continuously transmit satellite position in space and accurate time 24 hours a day.

GPS provides a signal that is processed in a GPS receiver, reading time, position and velocity. Location of the receiver is determined when at least four GPS satellite signals locked on receiver. It is then able to compute positions in three dimension.

GPS signal strength will determine the accuracy of the receiver. The greater the signal strength and number of signals received from the satellite, the more accurate the reading is, and vice versa.

For more information, please visit:
http://www.colorado.edu/geography/gcraft/notes/gps/gps_f.html