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Geoscience Australia
15 August 2006
Very
accurate
coordinates
of quasars
are
required!Collaboratio
n between
astronomers
and
geodesists!
New network benefit
Geoscience Australia
15 August 2006
ICRF (0.1 mas)
ITRF (1 mm)
geodetic network
Australian VLBI
more data
more sources
Australian geodetic datum
better positions of betterselected reference sourcesGPS
SLR
ATNF
New images
better referencesource selection
IVS, IAU
more data
New radiotelescope design
Geoscience Australia
- 12 meter dish (“Patriot”);
- High slew rate (~ 5 deg/sec);
- 5 deg elevation angle limit
- S/X band receiver;
- Near real-time VLBI (long-term
future);
- Broad band receiver (long-term
future);15 August 2006
Geoscience Australia
- is currently tested in Jet Propulsion
Laboratory (JPL);
- positive feedback after photogrammetry
of the primary reflector focus;
- good efficiency in X- and Ka-bands;
- fringe was found on 500-m baseline;
- more tests are being conducted
15 August 2006
12m Antenna at Patriot12m Antenna at Patriot
12m Antenna at Patriot12m Antenna at Patriot
Geoscience Australia
A pair of 12 m antennas operating at 2
Gbps will have exactly the same
sensitivity as a pair of 20m antennas
operating at a data rate of 256 Mbps.
15 August 2006
New Mark5B+ recorder is focused
to reach the 2 Gbps data rate
Mark 5 Upgrade Costs
Target
Existing
Mk5A Mk5B Mk5B+
0 $16.3K ~$18-20K ~$20-22K
Mk5A - ~$2-2.5K(Mk5B I/O)
~$11.5-12K
(Mk5B I/O plus
Amazon)
Mk5B - - ~$9555
(Amazon)
Note: Does not include external cabling costs, typically a few hundred dollars
Simulations
Geoscience Australia
- Realistic schedule (simulated data made in
NASA);
- six Northern hemisphere sites;
- Hartrao (South Africa);
- Selection of Australian and New Zealand
sites;
- Hobart: two options (“old” - existing; “new”
- proposed)
15 August 2006
Geodetic results (Hobart)
Geoscience Australia
15 August 2006
Hobart height component accuracy
# option
1 2 3 4 5 6
cm
0.6
0.8
1.0
1.2
1.4
1.6
Hobart horizontal component accuracy
# option
1 2 3 4 5 6cm
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
latitudelongitude
1 - “old” Hobart 3 – “old” Hobart + new site 5 – three new sites2 - “new” Hobart 4 – “new” Hobart + new site 6 – four new sites (+NZ)
Geodetic results (Yarragadee)
Geoscience Australia
15 August 2006
1 – Yarra single 3 – three new Australian sites2 – Yarra + “new” Hobart 4 – four new sites (+NZ)
Yarragadee height component accuracy
# options
1 2 3 4
cm
0.7
0.8
0.9
1.0
1.1
1.2
1.3
Yarragadee horizontal component accuracy
# options
1 2 3 4cm
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Latitudelongitude
How many new dishes?
Geoscience Australia
Three new dishes would provide
- 10% more accuracy in height component;
- 20% more accuracy in horizontal
components;
- more flexible schedules;
- parallel observations by two dishes in
Hobart would help to study the old Hobart
telescope’s mechanical and thermal
deformations, allowing revision of the
historical data records.15 August 2006