  We present the cosmological distance errors achievable using the baryon
acoustic oscillations as a standard ruler. We begin from a Fisher matrix
formalism that is upgraded from Seo & Eisenstein (2003). We isolate the
information from the baryonic peaks by excluding distance information from
other less robust sources. Meanwhile we accommodate the Lagrangian displacement
distribution into the Fisher matrix calculation to reflect the gradual loss of
information in scale and in time due to nonlinear growth, nonlinear bias, and
nonlinear redshift distortions. We then show that we can contract the
multi-dimensional Fisher matrix calculations into a 2-dimensional or even
1-dimensional formalism with physically motivated approximations. We present
the resulting fitting formula for the cosmological distance errors from galaxy
redshift surveys as a function of survey parameters and nonlinearity, which
saves us going through the 12-dimensional Fisher matrix calculations. Finally,
we show excellent agreement between the distance error estimates from the
revised Fisher matrix and the precision on the distance scale recovered from
N-body simulations.
