03/000

First geodetic results from the AuScope VLBI network

Oleg Titov

Australian Government

Geoscience Australia

UTAS, Hobart,

20 June 2012

Geoscience Australia

20 June 2012

Geoscience Australia

20 June 2012

The concept

;cos12 c

BTT

1T

Geoscience Australia

18 October 2010

B

B = 10000 km,

= 0.03cos sec

2T

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

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

VLBISLR

GPSDORIS

Geoscience Australia

20 June 2012

ITRF2005 Velocity field

AuScope project densificationAuScope project densification

Australian – New Zealand network

Geoscience Australia

20 June 2012

12m Antenna at Patriot12m Antenna at Patriot

The “dish” at workThe “dish” at work

12m Antenna at Patriot12m Antenna at Patriot5 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

Geoscience Australia

20 June 2012

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

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

Hobart12 – X component

Geoscience Australia

20 June 2012

X - component

Year

2011.0 2011.2 2011.4 2011.6 2011.8 2012.0 2012.2 2012.4

met

er

-0.90

-0.85

-0.80

-0.75

-0.70

-0.65

Hobart12 – Y component

Geoscience Australia

20 June 2012

Y-component

Year

2011.0 2011.2 2011.4 2011.6 2011.8 2012.0 2012.2 2012.4

met

er

1.12

1.14

1.16

1.18

1.20

1.22

1.24

Hobart12 – Z component

Geoscience Australia

20 June 2012

Z-component

Year

2011.0 2011.2 2011.4 2011.6 2011.8 2012.0 2012.2 2012.4

met

er

-8.20

-8.15

-8.10

-8.05

Hobart12 (ITRF2005)

Geoscience Australia

20 June 2012

Component VLBIGPS + local tie

(26-Nov-09)VLBI - GPS

X (meter)-3949990.683 +/-

0.014-3949990.675 +/-

0.004-0.008 +/- 0.014

Y (meter)2522421.181 +/-

0.0082522421.199 +/-

0.003-0.018 +/- 0.009

Z (meter)-4311708.161 +/-

0.013-4311708.170 +/-

0.0030.009 +/- 0.013

Reference epoch T = 2009.904

Hobart12 (ITRF2005)

Geoscience Australia

20 June 2012

ComponentHobart26

(ITRF2005)Hobart12

Hobart26-Hobart12

VX (cm/y) -3.95 -4.1 +/- 0.8 0.2 +/- 0.8

VY (cm/y) 0.91 0.4 +/- 0.50.5 +/- 0.5

VZ (cm/y) 4.15 4.5 +/- 0.8 0.4 +/- 0.8

Tectonic velocities

Hobart12 (ITRF2005)

Geoscience Australia

20 June 2012

Component X Y Z

σ (cm) 1.4 0.8 1.3

Weighted rms (cm)

2.4 1.3 2.2

Error budget?

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

Kath12M – X component

Geoscience Australia

20 June 2012

Year

2011.4 2011.6 2011.8 2012.0 2012.2

met

er

-4.70

-4.65

-4.60

-4.55

-4.50

Kath12M – Y component

Geoscience Australia

20 June 2012

Year

2011.4 2011.6 2011.8 2012.0 2012.2

met

er

2.30

2.35

2.40

2.45

2.50

Kath12M – Z component

Geoscience Australia

20 June 2012

Year

2011.4 2011.6 2011.8 2012.0 2012.2

met

er

-3.34

-3.32

-3.30

-3.28

-3.26

-3.24

-3.22

-3.20

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

Yarra12M – X component

Geoscience Australia

20 June 2012

Year

2011.2 2011.4 2011.6 2011.8 2012.0 2012.2

met

er

-6.20

-6.18

-6.16

-6.14

-6.12

-6.10

-6.08

-6.06

-6.04

-6.02

-6.00

Yarra12M – Y component

Geoscience Australia

20 June 2012

Year

2011.2 2011.4 2011.6 2011.8 2012.0 2012.2

me

ter

9.85

9.90

9.95

10.00

10.05

Yarra12M – Z component

Geoscience Australia

20 June 2012

Year

2011.2 2011.4 2011.6 2011.8 2012.0 2012.2

met

er

-1.00

-0.98

-0.96

-0.94

-0.92

-0.90

-0.88

-0.86

-0.84

Baseline Hobart12 - Kath12M (ICRF2 reference radio

sources)

Geoscience Australia

20 June 2012

Year

2011.4 2011.6 2011.8 2012.0 2012.2

3431

870

+..

. (m

eter

)

8.96

8.98

9.00

9.02

9.04

Hobart12 - Katherine (distant reference radio

sources, z>1.7)

Geoscience Australia

20 June 2012

Year

2011.4 2011.6 2011.8 2012.0 2012.2

3431

870

+ .

.. (

met

er)

8.92

8.94

8.96

8.98

9.00

9.02

9.04

Hobart12 - Katherine

Geoscience Australia

20 June 2012

Reference sources

Baseline rate (cm/year)

295 ICRF2 -3.8 +/- 1.3

4810 z>1.7 -1.6 +/- 1.9

GPS

(2010-2012) -0.3 +/- 0.7

Baseline evolution

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

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

ICRF1 catalogue (1998)

Geoscience Australia

20 June 2012

1.212 defining sources with the floor positional accuracy ~0.25 mas

2.294 candidate sources

3.102 other sources

608 sources separated into 3 groups

ICRF2 catalogue (1998)

Geoscience Australia

20 June 2012

1.295 defining sources with the positional accuracy ~0.04 mas

2.922 “non-defining” sources

3.1217 VCS sources

3414 sources separated into 3 groups

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

degrees

-80 -60 -40 -20 0 20 40 60 80

as

40

60

80

100

120

140

160

180

cos

ICRF2 non-defining sources (922)

Geoscience Australia

20 June 2012

degrees

-80 -60 -40 -20 0 20 40 60 80

as

200

400

600

800

1000

1200

1400

1600

1800

2000

cos

2145+067

1994 1996 1998 2000 2002 2004

as

-2000

-1000

0

1000

2000

20 June 2012

ICRF source instability(quasar 2201+315)

Variations of the 2201+315, RA

Year

2000 2001 2002 2003 2004 2005 2006

as

-2000

-1500

-1000

-500

0

500

1000

1500

Geoscience Australia

20 June 2012

Variations of the 2201+315, DEC

Year

2000 2001 2002 2003 2004 2005 2006

as

-2000

-1500

-1000

-500

0

500

1000

1500

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

Geoscience Australia

20 June 2012

Shift

~1.2 mas

( ~3.5 cm )

other

stable

# 3

as

-1000-50005001000

as

-1000

-500

0

500

1000

Daily dataApproximation

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

20 June 2012

Dipole component – 6.4 +/- 1.5 μas/year

Titov, Lambert, Gontier A&A 529, A91 (2011) Theory 46 μas/year

Total displacement is up to

~130 μas for 22 years since 1990

Systematic proper motion

20 June 2012

Quadrupole component ??

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