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Australian Government Geoscience Australia. First geodetic results from the AuScope VLBI network Oleg Titov. UTAS, Hobart, 20 June 2012. 03/000. Geoscience Australia. 20 June 2012. Geoscience Australia. 20 June 2012. The concept. . . B. B = 10000 km ,  = 0.03 cos sec.

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Australian Government

Geoscience Australia

First geodetic results from the AuScope VLBI network

Oleg Titov

UTAS, Hobart,

20 June 2012

03/000


Geoscience Australia

20 June 2012


Geoscience Australia

20 June 2012


The concept

B

B = 10000 km,

 = 0.03cos sec

Geoscience Australia

18 October 2010


Correlation

Time delay:

 = T’ - T

Disk 1

Output values:

- Time delay and its error

- Amplitude and phase

- Cross-correlation

- etc.

Disk 2

Geoscience Australia

20 June 2012


Local tie

Geoscience Australia

20 June 2012


Reference Frames :co-location

  • At sites where the technique are co-located (<300 metres apart) a millimetre level connection is measured using classical geodetic techniques

  • This provides the link between the measurement techniques

  • In Australia GA routinely undertakes these surveys at Tidbinbilla, Yarragadee, Hobart, Mount Stromlo

DORIS

GPS

VLBI

SLR


ITRF2005 Velocity field

Geoscience Australia

20 June 2012


AuScope project densification


Australian – New Zealand network

Geoscience Australia

20 June 2012


12m Antenna at Patriot


The “dish” at work


12m Antenna at Patriot

5 deg/sec in azimuth, 1.5 deg/sec in elevation


AuScope network

  • Hobart12 – started operation in tag along mode in October 2010; in full mode – January, 2011

  • Yarragadee – since 26 May, 2011

  • Katherine – since 16 June, 2011;

  • Astrometric problems are likely to contribute to the total geodetic error budget

20 June 2012


Hobart12

Mostly for IVS-R1, R4 sessions (EOP)AstrometryRegional geodesy

In total we have 78 ‘good’ session From 50 to 635 observations per session

Geoscience Australia

20 June 2012


Hobart12 – X component

Geoscience Australia

20 June 2012


Hobart12 – Y component

Geoscience Australia

20 June 2012


Hobart12 – Z component

Geoscience Australia

20 June 2012


Hobart12 (ITRF2005)

Reference epoch T = 2009.904

Geoscience Australia

20 June 2012


Hobart12 (ITRF2005)

Tectonic velocities

Geoscience Australia

20 June 2012


Hobart12 (ITRF2005)

Error budget?

Geoscience Australia

20 June 2012


Kath12M

In total we have 24 ‘good’ session From 104 to 700 observations per session

Not properly tied to ITRF2005

Geoscience Australia

20 June 2012


Kath12M – X component

Geoscience Australia

20 June 2012


Kath12M – Y component

Geoscience Australia

20 June 2012


Kath12M – Z component

Geoscience Australia

20 June 2012


Yarra12M

In total we have 12 ‘good’ session From 28 to 452 observations per session

Not properly tied to ITRF2005

Geoscience Australia

20 June 2012


Yarra12M – X component

Geoscience Australia

20 June 2012


Yarra12M – Y component

Geoscience Australia

20 June 2012


Yarra12M – Z component

Geoscience Australia

20 June 2012


Baseline Hobart12 - Kath12M (ICRF2 reference radio sources)

Geoscience Australia

20 June 2012


Hobart12 - Katherine (distant reference radio sources, z>1.7)

Geoscience Australia

20 June 2012


Hobart12 - Katherine

Baseline evolution

Geoscience Australia

20 June 2012


Internal vs external accuracy

For X, Y, Z components – external accuracy looks more then internal

Baseline lengths are sensitive to selection of reference radio sources

Geoscience Australia

20 June 2012


Internal vs external accuracy

May be caused by uncertainty of the reference radio sources in the southern hemisphere

Rotation of the whole Australian subnetwork due to astrometric instability of the reference sources, or just poor astrometric positions

Geoscience Australia

20 June 2012


ICRF1 catalogue (1998)

608 sources separated into 3 groups

  • 212 defining sources with the floor positional accuracy ~0.25 mas

  • 294 candidate sources

  • 102 other sources

Geoscience Australia

20 June 2012


ICRF2 catalogue (1998)

3414 sources separated into 3 groups

  • 295 defining sources with the positional accuracy ~0.04 mas

  • 922 “non-defining” sources

  • 1217 VCS sources

Geoscience Australia

20 June 2012


First catalogue (Ma et al., 1990)


ICRF1 defining sources

Geoscience Australia

20 June 2012


ICRF2 sources


ICRF2 defining sources (295)

Geoscience Australia

20 June 2012


ICRF2 non-defining sources (922)

Geoscience Australia

20 June 2012


2145+067

20 June 2012


ICRF source instability(quasar 2201+315)

Geoscience Australia

20 June 2012


ICRF source instability(quasar 2201+315, in plane, 2001-2004)

other

stable

# 3

Shift

~1.2 mas

( ~3.5 cm )

Geoscience Australia

20 June 2012


Systematic proper motion (555 sources)

20 June 2012


Systematic proper motion (40 best sources)

20 June 2012


Systematic proper motion(555 sources)

20 June 2012


Systematic proper motion

Dipole component – 6.4 +/- 1.5 μas/year

Titov, Lambert, Gontier A&A 529, A91 (2011)

Theory 46 μas/year

Total displacement is up to

~130 μas for 22 years since 1990

20 June 2012


Systematic proper motion

Quadrupole component ??

20 June 2012


Conclusion

  • Geodesy

  • Astrometry

20 June 2012


Geodesy

  • AuScope network operates successfully in spite of some technical problems;

  • Geodetic positions for Hobart12 were calculated (ITRF2005) with accuracy ~ 1 cm;

  • A good consistency with independent (GPS + local tie) results;

  • Astrometric problems are likely to contribute to the total error budget

20 June 2012


Astrometry

  • Number of the ICRF2 reference radio sources in the southern hemisphere in sufficient;

  • Positional accuracy needs to improved;

  • We should keep an eye on the observational schedules and, particularly, on the source selection

20 June 2012


Proposal

  • Do we need a special project (UTAS and GA) to select more stable reference radio sources?

20 June 2012


Practical steps

  • To check out existing time series of the reference radio source positions;

  • To run more sessions (AuScope + Parkes + Warkworth + Hartrao) to get more observations of the reference radio sources and extend the list;

  • To revise the existing list of reference radio sources (in cooperation with IVS-IERS-IAU);

20 June 2012


Thank you!

20 June 2012


Earthquake in Chile – 27-Feb-2010

20 October 2010


Earthquake in Japan – 11 March 2011

20 October 2010


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