Global Positioning System Flashcards
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
GPS Segments
Space Segment
User Segment
Control Segment
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
User Segment
Receivers that decode the signals from the satellites Task: Selecting satellites acquiring GPS signals Measuring and tracking Recovering navigation data
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
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)