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SOLVE BASELINE

      CLIC\SOLVE BASELINE [/OFFSET b1 dx1 dy1 dz1 b2  ...]
      [/SEARCH range] [/POLYNOMIAL degree]

  This uses a linear method to determine baselines. The baselines to be  de-
  termined must have been selected by the SET BASELINE command, and the data
  plotted; plot axes must have been previously selected by : SET X  HOUR_AN-
  GLE  DECLINATION  and  SET Y PHASE. With SET ANTENNA in action the antenna
  position offsets are directly fitted to the antenna phases, ensuring base-
  line closure.

  The  fitting  should  work  only  if the starting values are within half a
  wavelength in any direction of the true values. Use option /OFFSET to cor-
  rect the phases for an offset (dx1,dy1,dz1) in baseline b1 before fitting.
  This is needed if the baseline was wrong by more than half  a  wavelength.
  Offsets are to be given in meters.

  The  results are given as offsets in  meters  to  be  added  to  the base-
  line  used  for  data  acquisition (which may be read by SIC\EXAMINE BASE-
  LINE).   The  total  fitted baseline is also given in meters,  as  well as
  the  rms  of  the residuals in phase units.  Two sets of offsets are  giv-
  en:   the first set (dx, dy, dz) are the offsets with respect  to  the an-
  tenna  positions actually used, while the secoond set  (DX,  DY,  DZ)  are
  with  respect  to the standard antenna coordinates (the default values  in
  OBS).

  The /SEARCH option  enables  an  automatic  search  with  starting offsets
  scanning  a  3-d  box  in dx, dy, dz, by steps of half a wavelength in the
  three directions.  The argument range is in  meters   (scanning   is  from
  -range/2  to  +range/2,  default -0.005 to 0.005).  Only the solution with
  the minimum rms is kept.

  With option /POLYNOMIAL degree, and  if  SET  X  TIME  is  used  in  addi-
  tion  of  HOUR_ANGLE and DECLINATION, a polynomial function of time is in-
  cluded in the phase function being fitted.  The degree may range   from  0
  (the  default)  to  3.   In that case command RESIDUALS will also plot the
  residuals as a function of time.

  Use command RESIDUALS BASELINE to display the fit residuals (phase  should
  be  constant). Use later command PRINT BASELINE to create a procedure file
  (named CLIC-BASELINE.OBS) containing the antenna position  offsets.   This
  procedure file may be executed by the observing program OBS on the control
  computer bure01.

  If one specify elevation as an additional X variable (e.g. SET X  HOUR_AN-
  GLE  DECLINATION  TIME ELEVATION), then an additional parameter is fitted:
  the offsets between elevation and azimuth axes (or rather the  differences
  between  antennas).  These differing offsets result in a phase effect pro-
  portional to the cosine of elevation. In antenna mode, these  offsets  are
  given  for  each antenna in meters. In baseline mode, only differences are
  computed. To further correct for this effect use the command MODIFY  AXES.


Gildas manager 2011-09-07