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Correlator Products

Correlator Output

What: Once correlation is completed and the data quality assurance have been completed, data will be released to the PI(s) in the standard FITS format. Additional documentation from the correlator and RSOG will notify the PI of where additional files and assistance can be obtained.

How: FITS format on DAT or Exabyte tapes.

When: As soon as the correlator is satisfied with the correlator output.

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Correlator Feedback

Quality Assurance Data

What: Each correlator will perform a series of checks on the correlator output. Sub-sets of the data may be made available for analysis. Any problems with a particular GTS or GRT will be reported to the RSOG and the affected mission element.

How: Format differs among correlators.
For the Canadian correlator, files are listed in University of Calgary FTP Directory Structure. Requests by other mission elements for specific data not included in the DQA reports should be made be emailing These requests will be handled on a case-by-case basis.

When: As soon as correlation and checking is complete.

Where: For the Canadian correlator, files are listed in University of Calgary FTP Directory Structure.

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Correlator Output Files

What: The correlator will provide feedback to the mission elements in the form of correlator output files.

How: Format differs among correlators.

When: As soon as the correlator is satisfied with the correlation of the data.

Where: Files will be placed on the correlator's FTP site.

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VLBI Tape Management

What: Each correlator will maintain a data base including the status of all VLBI tapes under its control. The data base will be kept current by personnel at all mission elements, who have the responsibility to enter all changes in tape status (e.g. shipped or received) at their mission element.

How: For the VLBA, using the TRACK software. For S2 tapes, and email should be sent to listing the site/station name, date, tape serial numbers/root tape-ids, shipment waybill number, destination.

When: When tapes are shipped or received.

Where: TRACK can be operated via its WWW interface at - a password is necessary.

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VLBI Tapes

What: After correlation, the VLBI tapes will be erased and returned to the tape pool of that correlator. The correlators will distribute tapes to mission elements based on the Observation Summary File produced by the RSOG (Observation Summary File) to ensure each element has enough tapes to support SVLBI observations. These tape shipments will be logged on the tape management databases (VLBI Tape Management).

How: Tape labelling and shipping schemes are available by e-mail from for VLBA tapes and are given in "S2 SVHS Tape Handling Overview for RadioAstron" for S2 tapes. Shipping addresses for correlators are given in References and Documentation.

When: Tapes will be distributed to the global tape pool and sent out to mission elements at least once per week.

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Near Real-Time Fringe Detector Results

What: During the mission, it will be necessary to have periodic and quick checks of the SRT performance using the near real-time fringe detectors at Usuda, Sagamihara and Green Bank. These single baseline correlators will provide prompt checks of the satellite's health. Delays and delay rates will be made available, together with details of the orbit used, to correlators and navigation teams.

How: TBD

When: Results reported within TBD days of the observation.

Where: TBD

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Correlator Status Reports

What: Each correlator will inform the RSOG of the status of correlating the space VLBI experiments. These status reports will include the release date of data to PIs (which defines the proprietary period for the data), and note any anomalies detected or delays experienced during correlation.

How: Reports are named YYMMDDxxxx.sco where YYMMDD is the date of the report, and xxxx identifies the correlator. Suggested format as given in GTS Status Reports.

When: File will describe activities since the previous report, i.e. nominally activities for each Monday through Sunday UTC period.

Where: Emailed to, and/or placed on the correlator's FTP site.

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