1. GPS Global Positioning System- is a satellite navigation system that is used to compute the exact latitude and longitude position of any place on Earth. Many cars today are equipped with GPS systems. General Motors invented OnStar which is so popular it is starting to appear in vehicles other then GM

2. How does it work? The Global Positioning system is a satellite- based position-finding system operated by the US government. The first satellite was launched in 1978 with the hope of 24 more satellites being launched by 1994. Each satellite was the lifespan of 10 years, and new ones are needed continuously. These satellites are positioned so any one place on earth is in range of at least four satellites. Originally GPS was made for military use, but was made available for civilian use by the mid 80’s.

3. GPS is made up of orbiting satellites which provide navigation data around the clock. The satellites send radio signals to Earth that a GPS unit uses to calculate its latitude and longitude. Each satellite’s signal contains the exact time it was sent. A GPS unit uses this time to measure and calculate the distance of the satellite. Signals from at least three satellites are needed by a GPS unit to determine its location. As GPS technology is becoming more and more sophisticated the more accurate and expensive GPS systems have an accuracy of less then one centimeter.

4. GPS Applications The simplest GPS unit determines and stores locations as latitude/longitude positions. They are also able to store waypoints. A waypoint is a stored location that is of interest to the user. The GPS is also able to tell you the distance and direction of a waypoint from your current position. More complex GPS devices combine GPS capability with interactive map databases, providing the GPS with location to various landmarks such as streets, stores, gas stations, etc.

5. GPS Uses Agriculture – tractors, steered by GPS rather than people, are able to produced perfectly straight rows in half the time. Archaeology – used to record quickly and accurately the location of artifacts, allowing the data collected to draw quick and accurate maps of the digs. Forestry- used to plan forest cuts, ensuring the maximum amount of timber can be cut with minimum amount of environment damage.

6. Recreation- used for golf courses to indicate the distance from hazards and holes. Natural hazards - used to research and predict the occurrence of volcanic eruptions. Weather Forecasting- self explanatory