  The galaxy power spectrum is now a well-known tool of precision cosmology. In
addition to the overall shape, baryon oscillations and the small-scale
suppression of power by massive neutrinos capture complimentary information on
cosmological parameters when compared to the angular power spectrum of cosmic
microwave background anisotropies. We study both the real space and redshift
space galaxy power spectra in the context of non-linear effects and model them
based on the halo approach to large scale structure clustering. We consider
potential systematic in the cosmological parameter determination when
non-linear effects are ignored and the galaxy power spectrum is described with
the linear power spectrum scaled by a constant bias factor. We suggest that
significant improvements can be made when non-linear effects are taken into
account as a power-law contribution with two additional parameters to be
determined from the data. In addition to cosmological parameters through galaxy
clustering, such an approach allow a determination of useful information
related to astrophysics on how galaxies occupy dark matter halos.
