1. Global Position System By HengYu Lou

2. Video

3. History DOD (U.S. Department of Defense) 1978 to 1979 four GPS satellite 1979 to 1984 seven GPS satellite named BLOCK I 1993 21+3 GPS satellite is in space The Global Position System is finally finish

4. System GEO (Geocentric Orbit) 22,369 mile MEO (Medium Earth Orbit) between GEO and LEO LEO (Low Earth Orbit) 1,243 mile GPS 12,552 mile 21+3 1 Maine station 4 Ground Antenna 6 Monitor Station

5. Usage Construction Alarm system Navigation Weapon Car Boat Airplane

6. military GPS was build for military SPS (standard positioning service) PPS (Precise Positioning Service) SA (Selective Availability) 100 meter After 2000 cancel SA to 10 meter

7. Pro No weather effect Cover 98 percent of globe Three dimensions accuracy Fast Many usage Moveable

8. Con 24 satellites not enough Need at least three to work Not workable underground like tunnel

9. Question?

10. The End