QBToIDot:

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   Computes the quaternion derivative from angular velocity.
   Computes the time derivative of a quaternion that transforms from
   the body frame to the inertial frame given the angular velocity
   measured in the body frame.

   Since version 1.
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   Form:
   qD                 = QBToIDot( q, w )	
   [a, b, c, d, dqdt] = QBToIDot( q, w )
   [a, b, c, d, dqdt] = QBToIDot( q, w, dT )
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   ------
   Inputs
   ------
   q              (4,1)  Quaternion from b to a
   w              (3,1)  Rate of b with respect to a measured in b
   dT             (1,1)  Time step

   -------
   Outputs
   -------
   qD             (4,1)  Derivative of Q

   or

   a                     Plant matrix
   b                     Input matrix
   c                     Measurement matrix
   d                     Feedthrough matrix
   dqdt                  Constant quaternion derivative

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Children:

Common: Control/C2DZOH
Math: Linear/SkewSymm