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03/000 First geodetic results from the AuScope VLBI network Oleg Titov Australian Government Geoscience Australia UTAS, Hobart, 20 June 2012.

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Presentation on theme: "03/000 First geodetic results from the AuScope VLBI network Oleg Titov Australian Government Geoscience Australia UTAS, Hobart, 20 June 2012."— Presentation transcript:

1 03/000 First geodetic results from the AuScope VLBI network Oleg Titov Australian Government Geoscience Australia UTAS, Hobart, 20 June 2012

2 Geoscience Australia 20 June 2012

3 Geoscience Australia 20 June 2012

4 The concept Geoscience Australia 18 October 2010 B   B = km,  = 0.03 cos  sec

5 Correlation Geoscience Australia 20 June 2012 Disk 1 Disk 2 Output values: - Time delay and its error - Amplitude and phase - Cross-correlation - etc. Time delay:  = T’ - T

6 Local tie Geoscience Australia 20 June 2012

7 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 VLBI SLR GPS DORIS

8 Geoscience Australia 20 June 2012 ITRF2005 Velocity field

9 AuScope project densification

10 Australian – New Zealand network Geoscience Australia 20 June 2012

11 12m Antenna at Patriot

12 The “dish” at work

13 12m Antenna at Patriot 5 deg/sec in azimuth, 1.5 deg/sec in elevation

14 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

15 Hobart12 Geoscience Australia 20 June 2012 Mostly for IVS-R1, R4 sessions (EOP) Astrometry Regional geodesy In total we have 78 ‘good’ session From 50 to 635 observations per session

16 Hobart12 – X component Geoscience Australia 20 June 2012

17 Hobart12 – Y component Geoscience Australia 20 June 2012

18 Hobart12 – Z component Geoscience Australia 20 June 2012

19 Hobart12 (ITRF2005) Geoscience Australia 20 June 2012 ComponentVLBI GPS + local tie (26-Nov-09) VLBI - GPS X (meter) / / / Y (meter) / / / Z (meter) / / / Reference epoch T =

20 Hobart12 (ITRF2005) Geoscience Australia 20 June 2012 Component Hobart26 (ITRF2005) Hobart12 Hobart26- Hobart12 VX (cm/y) / /- 0.8 VY (cm/y) / /- 0.5 VZ (cm/y) / /- 0.8 Tectonic velocities

21 Hobart12 (ITRF2005) Geoscience Australia 20 June 2012 ComponentXYZ σ (cm) Weighted rms (cm) Error budget?

22 Kath12M Geoscience Australia 20 June 2012 In total we have 24 ‘good’ session From 104 to 700 observations per session Not properly tied to ITRF2005

23 Kath12M – X component Geoscience Australia 20 June 2012

24 Kath12M – Y component Geoscience Australia 20 June 2012

25 Kath12M – Z component Geoscience Australia 20 June 2012

26 Yarra12M Geoscience Australia 20 June 2012 In total we have 12 ‘good’ session From 28 to 452 observations per session Not properly tied to ITRF2005

27 Yarra12M – X component Geoscience Australia 20 June 2012

28 Yarra12M – Y component Geoscience Australia 20 June 2012

29 Yarra12M – Z component Geoscience Australia 20 June 2012

30 Baseline Hobart12 - Kath12M (ICRF2 reference radio sources) Geoscience Australia 20 June 2012

31 Hobart12 - Katherine (distant reference radio sources, z>1.7) Geoscience Australia 20 June 2012

32 Hobart12 - Katherine Geoscience Australia 20 June 2012 Reference sources Baseline rate (cm/year) 295 ICRF / z> /- 1.9 GPS ( ) /- 0.7 Baseline evolution

33 Internal vs external accuracy Geoscience Australia 20 June 2012 Baseline lengths are sensitive to selection of reference radio sources For X, Y, Z components – external accuracy looks more then internal

34 Internal vs external accuracy Geoscience Australia 20 June 2012 Rotation of the whole Australian subnetwork due to astrometric instability of the reference sources, or just poor astrometric positions May be caused by uncertainty of the reference radio sources in the southern hemisphere

35 ICRF1 catalogue (1998) Geoscience Australia 20 June defining sources with the floor positional accuracy ~0.25 mas candidate sources other sources 608 sources separated into 3 groups

36 ICRF2 catalogue (1998) Geoscience Australia 20 June defining sources with the positional accuracy ~0.04 mas “non-defining” sources VCS sources 3414 sources separated into 3 groups

37 First catalogue (Ma et al., 1990)

38 ICRF1 defining sources Geoscience Australia 20 June 2012

39 ICRF2 sources

40 ICRF2 defining sources (295) Geoscience Australia 20 June 2012

41 ICRF2 non-defining sources (922) Geoscience Australia 20 June 2012

42 June 2012

43 ICRF source instability (quasar ) Geoscience Australia 20 June 2012

44 ICRF source instability (quasar , in plane, ) Geoscience Australia 20 June 2012 Shift ~1.2 mas ( ~3.5 cm ) other stable # 3

45 Systematic proper motion (555 sources) 20 June 2012

46 Systematic proper motion (40 best sources) 20 June 2012

47 Systematic proper motion (555 sources) 20 June 2012

48 Systematic proper motion 20 June 2012 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

49 Systematic proper motion 20 June 2012 Quadrupole component ??

50 Conclusion Geodesy Astrometry 20 June 2012

51 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

52 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

53 Proposal Do we need a special project (UTAS and GA) to select more stable reference radio sources? 20 June 2012

54 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

55 Thank you! 20 June 2012

56 Earthquake in Chile – 27-Feb October 2010

57 Earthquake in Japan – 11 March October 2010


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