Dr Philip Collier

1
Introduction to Surveying (BPD)Global
Positioning System

• Dr Philip Collier
• Department of Geomatics
• The University of Melbourne
• p.collier_at_unimelb.edu.au
• Room D316

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Overview

• Basics of GPS
• Applications and uses
• GPS Segments

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What is GPS?

• NAVSTAR GPS - Navigation Satellite Timing and
  Ranging Global Positioning System
• All weather global navigation, positioning and
  time-transfer system
• Created and maintained by the US Department of
  Defense

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What does GPS provide?

• 3D position
• Navigation information
• position
• heading
• velocity
• Time

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What is GPS used for? ...
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In-car navigation
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Building/engineering set out
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Crustal motion
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Machine guidance
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Air navigation
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Mapping
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Deformation monitoring
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Missile guidance
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Capabilities of GPS
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Three GPS segments
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Space segment

• Constellation of 27 satellites (animation)
• Six orbital planes
• Altitude of approx. 20,200km
• Period of 11h 58m
• Atomic clocks accurate to 1x10-13 s/day

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Space segment
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Space segment
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Signal structure
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Control segment
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Control segment ...

• Monitor and control the constellation
• Establish and maintain GPS time
• Provide satellite location (ephemeris)

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Control segment ...
UPLOADNAVIGATIONMESSAGE
TRACK
Master Control Station
Ground Control Station
Monitor Station
Ground Control Station
Monitor Station
Ground Control Station
Monitor Station
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User segment

• Some examples already discussed
• Military applications include
• Navigation (land, sea, air)
• Missile guidance
• Search and rescue
• Civilian applications include
• Recreational uses (hiking, 4WD)
• Professional uses (from metres to millimetres)
• Position, dynamics, time

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Position from satellites
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Differential positioning
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Introduction to Surveying (BPD)Global
Positioning System

• Dr Philip Collier
• Department of Geomatics
• The University of Melbourne
• p.collier_at_unimelb.edu.au
• Room D316