  The measurement of the scale of the baryon acoustic oscillations (BAO) in the
galaxy power spectrum as a function of redshift is a promising method to
constrain the equation-of-state parameter of the dark energy w. To measure the
scale of the BAO precisely, a substantial volume of space must be surveyed. We
test whether light-cone effects are important and whether the scaling relations
used to compensate for an incorrect reference cosmology are in this case
sufficiently accurate. We investigate the degeneracies in the cosmological
parameters and the benefits of using the two-dimensional anisotropic power
spectrum. Finally, we estimate the uncertainty with which w can be measured by
proposed surveys at redshifts of about z=3 and z=1, respectively.
  In the simulated survey we find that light-cone effects are small and that
the simple scaling relations used to correct for the cosmological distortion
work fairly well even for large survey volumes. The analysis of the
two-dimensional anisotropic power spectra enables an independent determination
to be made of the apparent scale of the BAO, perpendicular and parallel to the
line of sight. This is essential for two-parameter w-models, such as the
redshift-dependent dark energy model w=w_0+(1-a)w_a. Using Planck priors for
the matter and baryon density and Delta(H_0)=5% for the Hubble constant, we
estimate that the BAO measurements of future surveys around z=3 and z=1 will be
able to constrain, independently of other cosmological probes, a constant w to
~ 12% and ~ 11% (68% c.l.), respectively.
