  The maximal symmetry of a quantum system with Heisenberg commutation
relations is given by the projective representations of the automorphism group
of the Weyl-Heisenberg algebra. The automorphism group is the central extension
of the inhomogeneous symplectic group with a conformal scaling that acts on
extended phase space. We determine the subgroup that also leaves invariant a
degenerate orthogonal Minkowski line element. This defines noninertial
relativistic symmetry transformations that have the expected classical limit as
c becomes infinite.
