Global Positioning System: An Overview

Parts of GPS system -Satellites -Ground Stations -User GPS receivers

Purposes of GPS systems -Locating -Navigation -Tracking -Mapping -Timing

Timing -All 24 satellites in constellation have atomic clocks. (There are 30 in the constellation as of 2010) -Ground stations synchronize all of the clocks for extremely accurate timing. -Satellites also target themselves (Doppler Effect)

How do Global Positioning Systems Work? -24 active satellites in MEO (Medium Earth Orbit) -11, 000 miles in orbit -All satellites inclined 55 degrees from equator

Triangulation Satellites use triangulation to locate point and time - All locations need four satellites to effectively triangulate position

GPS Constellation

Triangulation BEST better good

Geometric Dilution of Precision and other Reasons for GPS system failure

How do I use the GPS Receiver?

Military Uses  Originally Developed by the US Department of Defense (current GPS system)  Clear military purposes  Navigating missiles and combat airplanes  Strategic positioning and location of troops Locating vehicles (ships, tanks, ATV’s)

Commercial (Civilian) Uses  Guiding our cars, trains, trucks, boats, ships, and airplanes  Police use  Hikers *  Organizations and Companies  Farmers  Many more

Scientific Uses for GPS  Geoscience- -Seismology -Volcanology -Meteorology -Geodesy

Scientific Uses for GPS (cont’d)  Surveyors  Zoologists  Engineers  NASA  Astronomers

Future Uses  Backpacks are currently being developed to guide the blind through intricacies of major cities  Virtually unlimited possibilities  GIS systems-tracking data

Future Uses

Geocaching -An adventure for hikers using GPS systems -Started on May 3, 2000 by Dave Ulmer -Posted the event on a GPS internet users group

Geocaching -Beaver Creek, Oregon -N W Basic idea: hide a container in the woods and note coordinates using only GPS unit

“Take some stuff, leave some stuff”  Originally called, “The Great American Stash Hunt”  Mike Teague was the first to find “stash” left by Ulmer

Geocaching  Slashdot- on-line magazine for techies reported the event on Sept. 25, 2000  New York Times that October  Taken off and now is global phenomena  Geocaching.com

Benefits of GPS in the Classroom  Geography lessons-map the school/area  Mathematics  Social Studies-how areas have changed over time  Community Service

Benefits of GPS in the Classroom  What are some benefits you see for the classroom?  Get into groups and discuss options.  Be thinking of ideas during next lesson.  You will deliver your ideas to the class when we return

LET’S GO!!!!