GPS

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Global Positioning System (GPS)
Prof. Dr. Muhammed SAHIN http//atlas.cc.itu.edu
.tr/sahin
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Week Topics 1 Introduction to Space
Techniques 2 Introduction to GPS 3 GPS Observable
and mathematical models 4 GPS Observation
Techniques 5 Fieldwork 6 GPS Coordinate Systems
Datum Transformation 7 Error sources in
GPS 8 Fieldwork Data Processing 9 GPS Data
Processing 10 GPS Receiver Technologies 11 Midterm
Exam 12 GPS Project Management 13 Applications
of GPS 14 Earthquake Monitoring, Continuous
Reference Stations
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NUMBER OF ACTIVITIES THEIR CONTRIBUTION () TO
THE FINAL GRADE
Activities Contribution to the final grade
() Quiz 20 Project 20 Seminar 10 Fin
al Exam 50 70 attendance required!!...
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References (BOOKS)
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References (WEB pages)
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References (WEB pages)
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References (WEB pages)
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Introduction to Space Techniques
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Geodesy

• study of the size shape of the Earth
• determination of earth gravity field
• variation of earth surface
• precise positioning
• study of geodynamics (polar motion,
• earth rotation crustal deformation)
• performs all the objectives stated above using
• the earth orbiting satellites, including Moon and
• extra-galactic radio sources known as quasars.

Satellite geodesy, or space geodesy
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The World, 200 million years ago
NASA 1999
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Artificial Satellites in Space
Hight above earth (km) Satellite types
150 - 1 500 Remote sensing 1 500 - 20
000 Geodetic gt36 000 Communication
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Forces acting on a satellite
Moon
Sun
Earth-reflected radiation pressure of Sun
Asmospheric drag
Earth Ocean Loading
Direct radiation pressure of Sun
Non-spehericity of Earth
Earth
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Atmosphre
20 000 km
200 km
Ionosfer
Tropospher
50 km
Cloud
Earth
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History of Navigation Satellite Systems
1957 Launch of first satellite, SPUTNIK by former
Soviet Union 1957 TRANSIT system by USA 6 orbit
planes, 6 satellites, 1100 km above the
earth 1967 ZIKADE system by former USSR 6
orbit planes, 6 satellites, 1100 km above the
earth 1974 GPS by USA 6 orbit planes, 24
satellites, 20200 km above the earth 1976 GLONASS
by former USSR 6 orbit planes, 24 satellites,
20200 km above the earth
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GPS
24 satellites 6 orbiting planes 55 degree
inclination 20200 km above Earth 12 hours of
orbit 5 hours view in horizon
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GPS
COLORADO SPRINGS
HAWAII
KWAJALEIN
ASCENSION ISLAND
DIEGO GARGIA
MASTER CONTROL MONITORING
UPLOAD DOWNLOAD
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GLONASS

• is formed by 24 satellites located on three
  orbital planes.
• Each satellite is identified by its slot number,
  which defines the orbital plane (1-8, 9-16,17-24)
  and the location within the plane.
• The three orbital planes are separated by 120
  degrees.
• Within an 3 orbital plane, the 8 satellites are
  separated by 45 degrees.
• The GLONASS orbits are circular orbits 19,140 Km,
  with an inclination of 64.8 degrees and a period
  of 11 hours 15 minutes 44 seconds.

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Galileo

• Galileo will be Europes own global navigation
  satellite system, providing a highly accurate,
  guaranteed global positioning service under
  civilian control...
• The first experimental satellite, part of the
  so-called Galileo System Test Bed (GSTB) will be
  launched in late 2005.

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Galileo
- The fully deployed Galileo system consists of
30 satellites (27 operational 3 active spares),
positioned in three circular Medium Earth Orbit
(MEO) planes in 23616 km altitude above the
Earth, and at an inclination of the orbital
planes of 56 degrees with reference to the
equatorial plane.
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History of Laser Ranging Systems
Satellite Laser Ranging (SLR), 1964 Lunar Laser
Ranging (MOON), LLR Radio interferometric
systems very long baseline interferometry
(quasars stars), VLBI Satellitte Altimetry
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Satellite Laser Ranging (SLR)
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SLR Operation
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Satellite Laser Ranging (SLR)
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Laser satellites

• Starlette ( France, 1975 )
• Lageos-1 ( US, 1976 )
• Ajisai (Japan, 1986)Etalon-1,2 ( USSR, 1989
  )Topex/Poseidon ( US/Fr, 1992 )Lageos-2 (
  US/Italy, 1992 )Stella ( France, 1993 )

GPS-35,36 ( US, 1993/94 )Glonass-63,67 ( Russia,
1994 )ERS-2 ( ESA, 1995 )GFZ-1 ( 1996
)MIDORI/ADEOS (Japan,1996)TiPS ( US, 1996 )
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Most Commonly used satellites
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Laser stations used at ITU
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Lunar Laser Ranging (LLR)
Laser reflectors on the Moon
LLR observatories
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Lunar Laser Ranging (LLR)
Wettzell - Germany
McDonald - USA
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LLR targets on the Moon
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Very Long Baseline Interferometry (VLBI)
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International VLBI operations
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VLBI Antennas
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