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Australian Government Geoscience Australia. New geodetic VLBI dish in WA. 03/000. Existing VLBI facilities. Hobart (26 m) ~ 50 sessions/y - UTAS Parkes (64 m) ~ 1-3 sessions/y - ATNF Tidbinbilla (34 m) ~ 2-3 sessions/y - NASA. Geoscience Australia. 07 July 2005.

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03/000

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  1. Australian Government Geoscience Australia New geodetic VLBI dish in WA 03/000

  2. Existing VLBI facilities • Hobart (26 m) ~ 50 sessions/y - UTAS • Parkes (64 m) ~ 1-3 sessions/y - ATNF • Tidbinbilla (34 m) ~ 2-3 sessions/y - NASA Geoscience Australia 07 July 2005

  3. Problems • All dishes are operated by external agencies • No link between VLBI and SLR provided • Unsufficient geographic position • High elevation limits (Parkes): correlation between height and wet delay • General weakness of the ICRF in the southern hemisphere – uncertainty in VLBI and GPS heights for Hobart ~ 1 cm! • Design deterioration (Hobart) – low slewing speed, hydrogen maser instability, shape deformations, etc. Geoscience Australia 07 July 2005

  4. Key problem – slewing speed Mount [deg/min] [deg/min] ------------------------------------------------------- Hobart XYEW 40 20 HartRAO HADC 24 22 Kokee AZEL 120 120 ------------------------------------------------------- Geoscience Australia 07 July 2005

  5. Simulation Goddard Space Flight Center (NASA) Typical network: 6 dishes in Northern hemisphere + addition Geoscience Australia 07 July 2005

  6. Simulation Geoscience Australia 07 July 2005

  7. Simulation results Model sXp sYp sUT1 sNut1 sNut2 chi-sq Num (mas) (mas) (ms) (mas) (mas) ____________________________________________________________________ 6 st 0.118 0.098 0.0041 0.233 0.082 2.02 3290 6 st + Hartrao 0.101 0.061 0.0042 0.168 0.060 1.65 3179 46 deg/min 6 st + Hobart 0.081 0.069 0.0034 0.156 0.061 1.66 3442 60 6 st + Yarra 0.048 0.038 0.0027 0.112 0.047 1.65 4289 240 6 st + Y&Hart 0.045 0.031 0.0025 0.102 0.041 1.63 4494 6 st + Y&Hob 0.044 0.036 0.0026 0.101 0.043 1.59 4571 Geoscience Australia 07 July 2005

  8. Solution • New VLBI site in WA (Yarragadee) • Next generation radiotelescope to support remote unmanned real time VLBI operation • Diameter ~20-25 meter - Cost: 21-meter dish was ~3.1 Mill USD in prices of 2001 (5 Mill AUD in 2005??) • Operational costs ~300.000 AUD per year (can be shared with ATNF): 3 staff + equipment/service • OR diameter ~10-12 meter – less expansive Geoscience Australia 07 July 2005

  9. Goal • Hobart (26 m) ~ 50 sessions/y - UTAS • Parkes (64 m) ~ 1-3 sessions/y - ATNF • Tidbinbilla (34 m) ~ 2-3 sessions/y - NASA 2005 2010 • Yarragadee (20-25m) ~ 100-150 sessions/y - GA • Hobart (26 m) ~ 12 sessions/y - UTAS • Parkes (64 m) ~ 1-3 sessions/y - ATNF • Tidbinbilla (34 m) ~ 2-3 sessions/y - NASA Geoscience Australia 07 July 2005

  10. Advantages • Operated by GA - more flexibility in scheduling • Fast slew – more data, better precision • Link between VLBI and SLR, GPS - ITRF • Better geographic position • Better resolution in height and wet delay - ITRF • Strength on the ICRF - ICRF, ITRF • Measurement of the intracontinental deformations • Near-real time monitoring (e-VLBI) - timeliness • Collaboration with astronomers - stimulation of new joint research and programs • Leading role for VLBI in the southern hemisphere Geoscience Australia 07 July 2005

  11. Outcome in 5 years • ICRF – the number of reference sources in Southern hemisphere (factor by 2-3); • ICRF – precision (factor by 4-5); • ITRF – consistent multitechnique positions for all Australia VLBI sites on accuracy level of 1-2 mm; • Check of the intracontinental deformations; • Consistent multitechnique EOP; • Learning of seasonal deformations in region; • Tracing of troposphere and ionosphere; • In case of strong earthquake in WA – monitoring of post- and co-seismic deformations Geoscience Australia 07 July 2005

  12. Conclusion • Giant step forward in both directions • basic science; • public service Geoscience Australia 07 July 2005

  13. ICRF defining sources Geoscience Australia 07 July 2005

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