Welcome Students!
Dec 22, 2015
Earth’s Grid
Equator: line that divides the Earth into Northern and Southern hemispheres.
Prime Meridian: line that divides the Earth into Eastern and Western hemispheres.
What is GPS?
Hand held device used to communicate
with the satellites.
The location is given in
longitude and latitude
coordinates.
You Are
Here
Communication
The GPS handheld receiver uses radio waves to talk to the satellite and find its location.
State 3 =
Satellite 1 16 cm
Satellite 2 13 cm
Satellite 3 13.4 cm
Satellite 4 10.5 cm
State 1 =
Satellite 1 13 cm
Satellite 2 11 cm
Satellite 3 15 cm
Satellite 4 13.7 cm
State 2 =
Satellite 1 11 cm
Satellite 2 17.2 cm
Satellite 3 9 cm
Satellite 4 16 cm
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ColoradoMinnesota Missouri
How far???
GPS receivers use time to know how far away the satellites are.
Example: Lightening and Thunder in a storm.
How Far?• GPS satellites measure distance using the speed of light
• Light travels at 186,000 miles per second
• If it takes a signal 10 Seconds to travel from a GPS receiver to a GPS satellite, how far apart are they?
• 10 seconds x 186,000 miles per second = 1,860,000 miles
• The sun is 93,000,000 miles away…how long do you think it takes the light from the sun to reach Earth???
• 93,000,000 ÷ 186,000 = 8 minutes!
Bringing it all together
GPS can be used to tell us where we are on Earth
Why is GPS so important???
GPS uses time to find distance
Latitude and Longitude let us know exactly where we are.