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Flashcards in Global Positioning System Deck (6)
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1

Trilateration

Receivers calculate distances to satellites as a function of the amount of time it takes for satellites to reach the ground D=s*t

2

GPS Segments

Space Segment
User Segment
Control Segment

3

Space Segment

Orbits are arranged so that at any time, anywhere on Earth, there are at least four satellites visible in the sky.
27 Solar Satellites, 24 in operation, 3 extra in case of failure
Orbits 12,000 miles

4

User Segment

Receivers that decode the signals from the satellites
Task: Selecting satellites
acquiring GPS signals
Measuring and tracking
Recovering navigation data

5

Control Segment

Measures distances to satellite and send to the master control.
Determines: satellites orbits
clock performance
health of satellites
-Send commands and data to the constellation

6

How GPS Works

Receiver has to know two things: Location of at least three satellites above you
The distance between you and each of these satellites. Satellites transmit two signals on different frequencies(microwaves/radiowaves) that electromegneticly travel at the speed of light(186,000mps)