Use Case: ProcessSingleDishFocus


The Calibration Pipeline reduces Single Dish focus measurements and checks the solution validity in quasi-real time and in an automatic way.

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

Priority: ***

Performance: < seconds.

Frequency: seconds to hour.

Preconditions:

  1. The focus processing is initiated by the Calibration Pipeline main process.
  2. All observations belonging to the focus scan are available in temporary storage.
  3. Input: per observation and antenna
    • Pseudo-continuum (i.e. averaged spectral channels);
    • Associated subreflector axial positions;
    • System temperature;
    • Frequency.
  4. Input format has been verified in GetOnLineObservation.

Basic Course:

  1. Verification of input data consistency (e.g. did the subreflector moved during the scan).

    2. Exception Course: Processing is stopped and return a specific error code.
  2. The antenna-based corrections of subreflector position are computed together with uncertainties.

    3. Exception Course: Processing is stopped and return a specific error code.
  3. Verify whether solution is sensible (e.g. comparison of residual rms to theoretical noise; comparison of correction with wavelength) and return a quality flag.

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


Alternate Course: None.


Postconditions:

  1. Output:
    • Correction of subreflector position and associated uncertainty per antenna;
    • Quality flag;
    • Error code.


Issues to be Determined or Resolved:

  1. Does the focus computation needs any information about the position of antenna (in case of wind) ?
  2. Do we receive (on-off) data or (on and off) data here?
  3. Do we want atm-calibrated data?
    • Advantage: we can recover calibrator intensity and thus compute SNRs.
    • Inconvenient: more complicated scheme (i.e. need to go through atmospheric calibration first).

Notes:

  1. ***

Owner: Jerome Pety.
Last modified by $Author: lucas $ on $Date: 2003/02/14 12:13:08 $