GPS%20System%20Description

1
GPS System Description

• Space-based radio navigation system providing
• Precise position, velocity and time (pvt)
• Continuous, worldwide, 24 hour a day coverage
• Passive can serve an unlimited number of users
• All-weather operation
• U.S. Government system run by the DoD
  Adminstered by the U.S. Air Force
• Has large variety of defense and civil
  applications

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GPS Position Determination Technique
t2
X2, Y2, Z2
t3
Time for S1
X3, Y3, Z3
X1, Y1, Z1
t1
t4
GPS S3
X4, Y4, Z4
GPS S2
(P2)
(P3)
GPS S4
S1 Position (P1)
GPS S1
(P4)
R2
R3
R1
R4
User measures pseudoranges to satellites (R1,
R2, R3, R4)
User receives and stores data on satellite
locations (P1, P2, P3, P4) and their motion
P0
User tu
135.1-1 A504f
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Space Segment
GPS System Segments
User Segment
Monitor/ Uplink Stations
Colorado Springs ¹Hawaii Kwajalein Ascension
Island Diego Garcia ²Cape Canaveral, FL
Control Segment Headquarters Colorado
Springs Schriever AFB
Backup OCS Vandenberg AFB
¹ Monitor station only ² Uplink station only
Backup OCS Gaithersburg, MD
135.1-1/111-1 V006g
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The Navstar GPS Operational Constellation(24
Satellite Baseline Configuration)
Note As of 2004-05, there are about 28-30 S/C
in the constellation.
135.1-1/111-1 A401f
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Garmin iQue GPS
Palm OS