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