Global Positioning System:Global Positioning System:An OverviewAn 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

BESTbetter

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

FarmersMany more

Scientific Uses for GPS

Geoscience--Seismology-Volcanology-Meteorology-Geodesy

Scientific Uses for GPS (cont’d)

SurveyorsZoologistsEngineers

NASAAstronomers

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 45 17.460 W 122 24.800- 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 OctoberTaken off and now is global phenomena

Geocaching.com

Benefits of GPS in the Classroom

Geography lessons-map the school/areaMathematicsSocial Studies-how areas have changed over

timeCommunity 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!!!!