Use Case: ComputeProvisionalCalibrationCurves


The Calibration Pipeline fits polynomial through observations of phase calibrator on a given time interval. Fit is made in an automatic way for each baseline. The resulting calibration curves will be used by the quick look pipeline.

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

Priority: ***

Performance: seconds.

Frequency: minutes to hour.

Preconditions:

  1. The computation of Provisional calibration curves is initiated by the Calibration Pipeline at regular intervals.
  2. Input:
    • (WVR corrected) complex visibilities of one or several calibrators as a function of time;
    • Phase rms as a function of time???
    • Flag about rms weighting.

Basic Course:

  1. Verification of input data consistency (e.g. is the data regularly sampled with time?).

    2. Exception Course: Processing is stopped and return a specific error code.
  2. Define polynomial order depending on time interval.

    3. Exception Course: Processing is stopped and return a specific error code.
  3. Computes phase from complex visibilities.

    4. Exception Course: Processing is stopped and return a specific error code.
  4. Fits a polynomial through calibrator phases. A few mode are possible: i.e. with or without weighting and/or fitting of all calibrators at the same time or one calibrator at a time.

    5. Exception Course: Processing is stopped and return a specific error code.
  5. Verify whether solution is sensible (e.g. is that possible?) and return a quality flag.

    6. Exception Course: Processing is stopped and return a specific error code.
  6. Verify whether there is a systematic offset between fitting curves for each calibrator and set an alarm flag as this is an indication of wrong antenna position.

    7. Exception Course: Processing is stopped and return a specific error code.


Alternate Course:.


Postconditions:

  1. Output:
    • Polynomial order and set of coefficients with associated uncertainties;
    • Hour angle interval of validity;
    • Alarm code.
    • Error code.
  2. The output is fed back to the Calibration Pipeline.


Issues to be Determined or Resolved:

  1. ***

Notes:

  1. ***

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