  Future space-based gravity wave experiments such as the Big Bang Observatory
(BBO), with their excellent projected, one sigma angular resolution, will
measure the luminosity distance to a large number of gravity wave (GW) sources
to high precision, and the redshift of the single galaxies in the narrow solid
angles towards the sources will provide the redshifts of the gravity wave
sources. One sigma BBO beams contain the actual source only in 68 per cent
cases; the beams that do not contain the source may contain a spurious single
galaxy, leading to misidentification. To increase the probability of the source
falling within the beam, larger beams have to be considered, decreasing the
chances of finding single galaxies in the beams. Saini, Sethi and Sahni (2010)
argued, largely analytically, that identifying even a small number of GW source
galaxies furnishes a rough distance-redshift relation, which could be used to
further resolve sources that have multiple objects in the angular beam. In this
work we further develop this idea by introducing a self-calibrating iterative
scheme which works in conjunction with Monte-Carlo simulations to determine the
luminosity distance to GW sources with progressively greater accuracy. This
iterative scheme allows one to determine the equation of state of dark energy
to within an accuracy of a few percent for a gravity wave experiment possessing
a beam width an order of magnitude larger than BBO (and therefore having a far
poorer angular resolution). This is achieved with no prior information about
the nature of dark energy from other data sets such as SN Ia, BAO, CMB etc.
