WHY SPACE GEODESY? WHY SPACE GEODESY? 5 th ASSA Symposium November - - PowerPoint PPT Presentation

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WHY SPACE GEODESY? WHY SPACE GEODESY? 5 th ASSA Symposium November - - PowerPoint PPT Presentation

Sep 13, 2022 238 likes •895 views

SPACE GEODESY AT WHY SPACE GEODESY? WHY SPACE GEODESY? 5 th ASSA Symposium November 2002 Space Geodesy Programme Ludwig Combrinck Hartebeesthoek Radio Astronomy Observatory National Research Foundation South Africa http://www.hartrao.ac.za

slide-1
SLIDE 1

SPACE GEODESY AT

WHY SPACE GEODESY? WHY SPACE GEODESY?

5th ASSA Symposium

November 2002

Space Geodesy Programme Ludwig Combrinck Hartebeesthoek Radio Astronomy Observatory National Research Foundation South Africa

http://www.hartrao.ac.za

slide-2
SLIDE 2
  • What is Space Geodesy?
  • Multi-disciplinary applications
  • Three major space geodetic techniques
slide-3
SLIDE 3

Well, you all know what space is…….

  • Geodesy is a branch of applied mathematics
  • Uses the principles of mathematics, astronomy and physics
  • Applies them within the capabilities of engineering and technology
  • To determine exact positions of points, globally, the shape and size of the

earth

  • It studies the variations of terrestrial gravity
  • Space Geodesy has many other applications, meteorology, global warming etc.
slide-4
SLIDE 4
slide-5
SLIDE 5

So, Space Geodesy is multi-disciplinary…

  • earth rotation parameters
  • coordinates and velocities of stations
  • geocenter coordinates
  • parameters of the Earth’s gravity field
  • high accuracy satellite ephemerides
  • determination of fundamental physical constants

These products support scientific objectives including:

  • maintenance and realisation of ITRF
  • monitoring 3D deformations of the solid earth
  • monitoring earth rotation and polar motion
  • supports monitoring of mean sea level, wave heights, ice sheet thickness etc.
  • scientific satellite orbit determinations
  • climatological research
  • precise timing
slide-6
SLIDE 6

Well, now you all know what space geodesy is…….

  • Very Long Baseline Interferometry (VLBI)
  • Satellite Laser Ranging (SLR)
  • Global Positioning System (GPS)

SLR calibrates GRACE orbit GPS data at Sutherland used to measure long wavelength gravity, applied to GRACE

  • rbital modeling
slide-7
SLIDE 7
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SLIDE 8
  • Time delay t can be measured very accurately (MASER clock)
  • Need 3 equations, 3 different quasars, to find baseline vector
slide-9
SLIDE 9
  • Geodetic VLBI maintains the International Celestial Reference Frame
  • The ICRF consists of 212 radio sources, positional accuracy better than 1 mas
  • Adopted by the IAU as the fundamental CRF
  • Replaces FK5 optical frame as of 1 January 1998
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SLIDE 10
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SLIDE 11
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SLIDE 12
  • Ground based station transmits short (pico-second) laser pulse
  • The laser pulse is reflected off a retroreflector
  • The round trip time of flight is precisely measured
  • Corrected for atmospheric delay
  • Then a geometric range is calculated
slide-13
SLIDE 13
  • MOBLAS6 inauguration 20 November 2000
  • Achieved mission status 19th June 2001
  • Superior performance level July 2002 (> 200 passes/week)
  • Operate 16 hours/day, 7 days/week (114 hours)
  • Using GFZ IRVs and time bias functions for GRACE, CHAMP
slide-14
SLIDE 14
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SLIDE 15
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SLIDE 16
  • 5 IGS stations operational
  • IGS Data centre for Africa
  • TIGA Data centre
  • TIGA Associate Analysis Centre
  • SADC IGS Network, part of AFREF
  • Five new stations in progress
slide-17
SLIDE 17
slide-18
SLIDE 18
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SLIDE 19
  • Densification of the ITRF, contribute to AFREF
  • Install at least one IGS GPS station in each SADC country
  • Facilitate capacity building through collaboration
  • Establish a Geodetic Institute at HartRAO
  • GI can offer studentships, training, directed effort towards capacity building

Building with capacity, Vehicle Assembly Building (VAB) Kennedy Space Centre, Florida 160 metres tall, covers 3,25 Hectares To paint the flag and emblem took 6000 gallons of paint

slide-20
SLIDE 20
  • GPS at Tide Gauge project (TIGA)
  • HartRAO/GFZ earth-tide project at Sutherland
  • HartRAO/GFZ IGS installation in Namibia
  • New Project, Lunar Laser Ranging
  • Crustal stability at Vaalputs (HartRAO/NECSA)
  • Total zenith delay mapping for Weather Prediction (HartRAO/POTCH)
  • Okavango delta water level project (HartRAO, WITS, UCT, ORC)
  • other projects!
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SLIDE 21
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SLIDE 22
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SLIDE 23
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SLIDE 24
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SLIDE 25
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SLIDE 26
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SLIDE 27
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SLIDE 28
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SLIDE 29
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SLIDE 30
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SLIDE 31
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SLIDE 32
  • The ICRF realised by Geodetic VLBI is much more accurate, simpler and stable
  • It serves the purposes of astronomy and geophysics
  • VLBI, SLR and GPS together provide an International Terrestrial Reference Frame
  • Numerous branches of science are supported by Space Geodesy
  • And, you can use it while camping, hiking, sailing!
slide-33
SLIDE 33

SPACE GEODESY AT

WHY SPACE GEODESY? WHY SPACE GEODESY?

5th ASSA Symposium

November 2002

Space Geodesy Programme Ludwig Combrinck Hartebeesthoek Radio Astronomy Observatory National Research Foundation South Africa

http://www.hartrao.ac.za

slide-34
SLIDE 34
  • What is Space Geodesy?
  • Multi-disciplinary applications
  • Three major space geodetic techniques
slide-35
SLIDE 35

Well, you all know what space is…….

  • Geodesy is a branch of applied mathematics
  • Uses the principles of mathematics, astronomy and physics
  • Applies them within the capabilities of engineering and technology
  • To determine exact positions of points, globally, the shape and size of the

earth

  • It studies the variations of terrestrial gravity
  • Space Geodesy has many other applications, meteorology, global warming etc.
slide-36
SLIDE 36
slide-37
SLIDE 37

So, Space Geodesy is multi-disciplinary…

  • earth rotation parameters
  • coordinates and velocities of stations
  • geocenter coordinates
  • parameters of the Earth’s gravity field
  • high accuracy satellite ephemerides
  • determination of fundamental physical constants

These products support scientific objectives including:

  • maintenance and realisation of ITRF
  • monitoring 3D deformations of the solid earth
  • monitoring earth rotation and polar motion
  • supports monitoring of mean sea level, wave heights, ice sheet thickness etc.
  • scientific satellite orbit determinations
  • climatological research
  • precise timing
slide-38
SLIDE 38

Well, now you all know what space geodesy is…….

  • Very Long Baseline Interferometry (VLBI)
  • Satellite Laser Ranging (SLR)
  • Global Positioning System (GPS)

SLR calibrates GRACE orbit GPS data at Sutherland used to measure long wavelength gravity, applied to GRACE

  • rbital modeling
slide-39
SLIDE 39
slide-40
SLIDE 40
  • Time delay t can be measured very accurately (MASER clock)
  • Need 3 equations, 3 different quasars, to find baseline vector
slide-41
SLIDE 41
  • Geodetic VLBI maintains the International Celestial Reference Frame
  • The ICRF consists of 212 radio sources, positional accuracy better than 1 mas
  • Adopted by the IAU as the fundamental CRF
  • Replaces FK5 optical frame as of 1 January 1998
slide-42
SLIDE 42
slide-43
SLIDE 43
slide-44
SLIDE 44
  • Ground based station transmits short (pico-second) laser pulse
  • The laser pulse is reflected off a retroreflector
  • The round trip time of flight is precisely measured
  • Corrected for atmospheric delay
  • Then a geometric range is calculated
slide-45
SLIDE 45
  • MOBLAS6 inauguration 20 November 2000
  • Achieved mission status 19th June 2001
  • Superior performance level July 2002 (> 200 passes/week)
  • Operate 16 hours/day, 7 days/week (114 hours)
  • Using GFZ IRVs and time bias functions for GRACE, CHAMP
slide-46
SLIDE 46
slide-47
SLIDE 47
slide-48
SLIDE 48
  • 5 IGS stations operational
  • IGS Data centre for Africa
  • TIGA Data centre
  • TIGA Associate Analysis Centre
  • SADC IGS Network, part of AFREF
  • Five new stations in progress
slide-49
SLIDE 49
slide-50
SLIDE 50
slide-51
SLIDE 51
  • Densification of the ITRF, contribute to AFREF
  • Install at least one IGS GPS station in each SADC country
  • Facilitate capacity building through collaboration
  • Establish a Geodetic Institute at HartRAO
  • GI can offer studentships, training, directed effort towards capacity building

Building with capacity, Vehicle Assembly Building (VAB) Kennedy Space Centre, Florida 160 metres tall, covers 3,25 Hectares To paint the flag and emblem took 6000 gallons of paint

slide-52
SLIDE 52
  • GPS at Tide Gauge project (TIGA)
  • HartRAO/GFZ earth-tide project at Sutherland
  • HartRAO/GFZ IGS installation in Namibia
  • New Project, Lunar Laser Ranging
  • Crustal stability at Vaalputs (HartRAO/NECSA)
  • Total zenith delay mapping for Weather Prediction (HartRAO/POTCH)
  • Okavango delta water level project (HartRAO, WITS, UCT, ORC)
  • other projects!
slide-53
SLIDE 53
slide-54
SLIDE 54
slide-55
SLIDE 55
slide-56
SLIDE 56
slide-57
SLIDE 57
slide-58
SLIDE 58
slide-59
SLIDE 59
slide-60
SLIDE 60
slide-61
SLIDE 61
slide-62
SLIDE 62
slide-63
SLIDE 63
slide-64
SLIDE 64
  • The ICRF realised by Geodetic VLBI is much more accurate, simpler and stable
  • It serves the purposes of astronomy and geophysics
  • VLBI, SLR and GPS together provide an International Terrestrial Reference Frame
  • Numerous branches of science are supported by Space Geodesy
  • And, you can use it while camping, hiking, sailing!