The cosmological power spectrum of the coherent matter flow is measured exploiting an improved prescription for the apparent anisotropic clustering pattern in redshift space. New statistical analysis is presented to provide an optimal observational platform to link the improved redshift distortion theoretical model to future real data sets. The statistical power as well as robustness of our method are tested against 60 realizations of 8h^-3Gpc³ dark matter simulation maps mocking the precision level of upcoming wide-deep surveys. We showed that we can accurately extract the velocity power spectrum up to quasilinear scales of k∼0.1hMpc^-1 at z=0.35 and up to k∼0.15hMpc^-1 at higher redshifts within a couple of percentage precision levels. Our understanding of redshift space distortion is proved to be appropriate for precision cosmology, and our statistical method will guide us to a righteous path to meet the real world.