RHSX:

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   Right hand side for a one dimensional vertical motion simulation.
   Adds Gaussian random variations to the thrust.

   Since version 11.
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   Form:
   xDot = RHSX( x, t, d )
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   Inputs
   ------
   x             (2,1)  [x;v]
   t             (1,1)  Time (not used)
   d             (1,1)   Data structure
                         .m        (1,1) Mass
                         .g        (1,1) Acceleration of gravity
                         .tNoise   (1,1) Standard deviation of thrust
                         .t0       (1,1) Average thrust

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   Outputs
   -------
   xDot           (2,1)   State derivative

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