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Coordinate Systems

Convention

All coordinate systems apply a right-hand convention.

Global

Basin-fixed coordinate system with:

  • origin in the floater center position at the still water line
  • z upwards
  • x towards the wave maker (irrespective of floater heading)

The tags surge, sway, and heave refer to motions in this coordinate system

Local - globally oriented

Body-fixed coordinate system with:

  • origin in the floater center position at the still water line
  • z upwards
  • x towards the wave maker when floater is in zero position (irrespective of floater heading)

The tags roll, pitch, and yaw refer to motions in this coordinate system.

Local

Body-fixed coordinate system with:

  • origin in the floater center, baseline elevation
  • z upwards
  • x towards local direction corresponding to towards wave maker at heading zero

Local sensor position are given in this coordinate system. Floater heading is defined as the

Basin

Basin coordinate systems are dependent on the basin standard and the test specification Sensors may record motions in the basin coordinate system, but the definition of the positive direction will be given in one of the other coordinate systems.