  There are many different approaches to using observations to constrain or
determine the global cosmological parameters that describe our universe.
Methods that rely upon a determination of the coordinate distance to
high-redshift sources are particularly useful because they do not involve
assumptions about the clustering properties of matter, or the evolution of this
clustering.
  Two of the methods currently being used to determine the coordinate distance
to high-redshift sources are the radio galaxy method and the supernova method.
These methods are similar in their dependence on the coordinate distance. Here,
the radio galaxy method is briefly described and results are presented. One of
the underlying assumptions of the method is explored. In addition, the method
is compared and contrasted to the supernova method. The constraints imposed on
global cosmological parameters by radio galaxies are consistent with those
imposed by supernovae.
  For a universe that is spatially flat with mean mass density $\Omega_m$ in
non-relativistic matter and mean mass density 1- $\Omega_m$ in quintessence,
radio galaxies alone indicate at 84 % confidence that the expansion of the
universe is accelerating at the current epoch. And, independent of whether or
not the universe is spatially flat, radio galaxies alone indicate at 95 %
confidence that $\Omega_m$ must be less than 0.6 at the current epoch.
