Unambiguous angular momentum of radiative spacetimes and asymptotic structure in terms of the center of mass system

We present a definition of angular momentum for radiative spacetimes which does not suffer from any ambiguity of supertranslations. We succeed in providing an appropriate notion of {\it intrinsic} angular momentum; and at the same time a definition of center of mass frame at future null infinity. We use the center of mass frame to present the asymptotic structure equations for vacuum spacetimes.