Use Case: ProcessCalibratorPhase


The calibration pipeline compute from the complex visibilities measured on a calibrator :

  1. Phase RMS and decorrelation factors for each baseline;
  2. Phase structure function;
  3. Seeing.

It also desintangle atmospheric and detector contributions to phase rms.

Those computation must be done in an automatic way and in quasi-real time.

Role(s)/Actor(s):
Primary: Calibration Pipeline
Secondary: ***

Priority: ***

Performance: < second

Frequency: seconds

Preconditions:

  1. The processing of calibrator phase is initiated by the Calibration Pipeline after each scan on a phase calibrator.
  2. Input: per baseline and per integration time
    • Pseudo-continuum complex visibilities;
    • System temperature.

Basic Course:

  1. Verification of input data consistency (e.g. is there enough data to make meaningful statistics).

    2. Exception Course: Processing is stopped and return a specific error code.
  2. Compute temporal phase rms for each baseline.

    3. Exception Course: Return a specific error code and continue because spatial statistics may be done as we have so many antenna.
  3. Compute detector contribution from system temperature data and substract this contribution to the total phase rms to obtain atmospheric contribution.

    4. Exception Course: Return a specific error code and continue because spatial statistics may be done as we have so many antenna.
  4. Compute structure function (i.e. phase rms as a function of baseline length).

    5. Exception Course: Stop processing and return a specific error code.
  5. Compute the seeing with a TBD algorithm.

    6. Exception Course: Stop processing and return a specific error code.


Postconditions:

  1. Output:
    • Temporal phase rms for each baseline and its decomposition between detector and atmosphere; Associated uncertainties;
    • Phase structure function and associated uncertainties;
    • Seeing and associated uncertainties;
    • Error code for temporal computation.
    • Error code for spatial computation.
  2. The output is fed back to the Calibration Pipeline.


Issues to be Determined or Resolved:

  1. Pathlength rms could be output instead/or with phase rms.
  2. Seeing algorithm must be defined.

Notes:

  1. ***

Owner: Jerome Pety.
Last modified by $Author: lucas $ on $Date: 2002/11/16 09:27:09 $