1 What is GPS?. The Global Positioning System Constellation GPS is a global navigation satellite...
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1 What is GPS?. The Global Positioning System Constellation GPS is a global navigation satellite system developed by the U.S. Department of Defense, managed
The Global Positioning System Constellation GPS is a global
navigation satellite system developed by the U.S. Department of
Defense, managed by the U.S. Air Force. Free for anyone to use.
Provides geographic locations at any time, anywhere.
Slide 3
WGS 1984 Geographic Coordinate System Notation Degrees,
Minutes, Seconds (DMS) and Degrees, Minutes, Seconds (DMS) and
Decimal Degrees (DD) 0 0 0 N 45 0 0 0 0 0 N 90 0 0 S 90 0 0 S 45 0
0 0.0 45.0 90.0 -90.0 -45.0 E 90 0 0 E 180 0 0 W 90 0 0 W 180 0 0
0.0 90.0 180.0 -90.0 -180.0
Slide 4
The Global Positioning System Constellation GPS is a global
navigation satellite system developed by the U.S. Department of
Defense, managed by the U.S. Air Force. Free for anyone to use.
Provides geographic locations at any time, anywhere. 24 - 32 earth
orbiting satellites
Slide 5
A GPS satellite 5 Solar panels power Atomic clock precisely
records time in UTC Radio transmitter broadcasts a continuous
signal containing the time, and ephemeris (identification and
positional information)
Slide 6
San Diego Aerospace Museum 6 GPS satellite on display
Slide 7
The Global Positioning System Constellation GPS is a global
navigation satellite system developed by the U.S. Department of
Defense, managed by the U.S. Air Force. Free for anyone to use.
Provides geographic locations at any time, anywhere. 24 - 32 earth
orbiting satellites GPS receivers Contain a clock, computer, radio
wave receiver. Dime sized to dinner plate sized Receive signals
from GPS satellites Computes distance to satellite by comparing
time: signal sent vs. received. Receiving four satellite signals
allows a position calculation using trilateration
Slide 8
Trilateration location determination through the measurement of
distances. If the distance to 3 satellites is known, where these 3
spheres intersect can be calculated. Trilateration is the method
used by a GPS receiver to determine ones position on earth. Watch
the explanation by a NASA scientist:
http://www.youtube.com/watch?v=3zRlbboMvb0
Slide 9
GPS uses Navigation Penn State University Geospatial Revolution
Videos, Episode 1 (minutes 2:00 2:45)
http://geospatialrevolution.psu.edu/episode1/complete 9
GPS uses: Military Weapon targeting and guidance 12 Troop
deployment and navigation
Slide 13
Mission Planning to aid accuracy
Slide 14
GPS devices Survey, mapping, recreational Survey grade Very
sophisticated receivers, able to receive many signals. Centimeter
accuracy possible. Cost: several thousand $$. Mapping grade ~1
meter accuracy, possible. Cost: $700 and up. Recreational User
friendly, 10 meter accuracy. Cost: $100 and up.
Slide 15
GPS Summary 24 - 32 satellites in orbit at 20,200 km Continuous
24-hour, worldwide coverage Position and time data transmitted from
satellites through coded radio waves. Accuracy is depends on the
sophistication of the receiver, number of signals received, and
ranges from 10 meter to centimeter accuracy. Satellites controlled
by U.S. Dept. of Defense (clock adjustments, activation, signal
scrambling) WGS 1984 coordinate system used Wide range of
applications For a more involved presentation on GPS, go
herehere