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LISSAJOUS

    LISSAJOUS    xAmplitude   yAmplitude
      /CENTER    xCenter      yCenter
      /FREQUENCY frequencyX   frequencyY
      /PHASES    phiX         phiY
      /TOTF      tOtf
      /SYSTEM    system

    additionally for NIKA:

      /FOCUS     f1 f2 [... f18] [direction]
      /POINTING  [yes|no]
      /TUNE      xOffsetT     yOffsetT
      /TTUNE     tTune

    Specify an On-The-Fly (OTF) map with a Lissajous curve in 1 subscan.
    LISSAJOUS is at this time (2014-11-10) supported only for GISMO and NIKA

    Real      :: xAmplitude        ! amplitude for x-offsets
    Real      :: yAmplitude        ! amplitude for y-offsets
    Real      :: xCenter           ! center x-offset
    Real      :: yCenter           ! center y-offset
    Real      :: frequencyX        ! frequency    [Hz]  for x
    Real      :: frequencyY        ! frequency    [Hz]  for y
    Real      :: phiX              ! phase offset [rad] for x
    Real      :: phiY              ! phase offset [rad] for y

    Real      :: tOtf              ! time [s]
    Character :: systemName        ! name of system, one of:
                                   ! PROJECTION
                                   ! TRUEHORIZON

    Real      :: f1 f2 [... f18]   ! focus offset [mm] during each Lissajous cur
    Character :: direction         ! direction of focus offsets, one of:
                                   ! X
                                   ! Y
                                   ! Z

    Real      :: xOffsetT          ! x-offset for tune subscan
    Real      :: yOffsetT          ! y-offset for tune subscan
    Real      :: tTune             ! time [s] for tune subscan


    During a Lissajous OTF segment, the position offsets
    x and y as a function of time t are:

    x = xCenter + xAmplitude * SIN(2 Pi frequencyX t + phiX)
    y = yCenter + yAmplitude * SIN(2 Pi frequencyY t + phiY)

    SIN is the usual sine function, Pi is the number Pi.

    xAmplitude yAmplitude xCenter yCenter are in angle units ([arc sec])
    frequencyX frequencyY                 are in [Hz]
    phiX       phiY                       are in [rad]

    Note that the possible frequencies are very low,
    typically 0.01 to 0.15 Hz.

    At the start of a Lissajous subscan, paKo will insert a "ramp" along a
    straight line, i.e., a linear OTF segment, increasing the count of
    segments by 2.  This ramp up starts with speed 0 relative to the
    source and joins smoothly with the start position and velocity of the
    Lissajous segment.  The purpose is to avoid a sudden acceleration at
    the start of the Lissajous segment.  The inserted ramp up
    segment and the Lissajous segment become part of the same subscan.

    Lissajous curves with large amplitudes or frequencies can reach the
    antenna's speed and acceleration limits for tracking.  Lissajous
    curves can be executed only for elevations less than a maximum, which
    depends on the Lissajous parameters.  For information, this elevation
    condition is shown by pako. Even below the limits, during very fast
    Lissajous curves the tracking errors will be higher, several arc sec,
    than during most other observations.

    DO NOT TRY TO OBSERVE LISSAJOUS ABOVE THIS MAXIMUM ELEVATION.


Subsections

Gildas manager 2023-06-01