VLBI component of the NCRIS Australian Government Geoscience Australia 15 August 2006, Canberra.

VLBI component of the NCRIS

Australian Government

Geoscience Australia

15 August 2006, Canberra


15 August 2006

Very

accurate

coordinates

of quasars

are

required!Collaboratio

n between

astronomers

and

geodesists!

Radiotelescopes in Australia


15 August 2006

New network benefit


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


- 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

12m Antenna at Patriot12m Antenna at Patriot


- 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




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


- 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)


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)


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?


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

How many new dishes?


- International VLBI Service (IVS)

strongly supports the third new

dish

15 August 2006

32 or

VLBI component of the NCRIS Australian Government Geoscience Australia 15 August 2006, Canberra.

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Transcript of VLBI component of the NCRIS Australian Government Geoscience Australia 15 August 2006, Canberra.