1. GPS Example of how GPS works (Global Positioning System)

2. There are 24 satellites in orbit around the earth.

4. Suppose one knows that he is 625 miles from Boise, Idaho. That is the only information he has. Does he know where he is?

5. Now, suppose he knows that he is 690 miles from Minneapolis, Minnesota. Now, does he know where he is?

6. Now, let’s add that he knows that he is 615 miles from Tucson, Arizona. Now, does he know where he is?

7. GPS Satellites put out a signal three dimensional, not two dimensional like the flat circles, so it creates a sphere. Because it creates overlapping spheres the GPS unit can tell elevation in addition to longitude and latitude.

8. Satellites circling the earth.

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12. Cartesian Coordinate System

14. Vocabulary: CITO- Cache In Trash Out Waypoint- Reference point for a physical location on earth Muggled- The act of vandalizing or stealing a cache Travel bug- A trackable tag that may be attached to a item in a geocache GPS- Global Positioning System Coordinate- Any of the magnitudes that serve to define a position of a point Geocaching- A world wide game of hiding and seeking treasures BYOP- Bring your own pen/pencil