  We present a brief survey of some results on electroweak properties of
composite systems that are obtained in the frameworks of our version of the
instant form of relativistic quantum mechanics (RQM). Our approach describes
well the $\pi$- and the $\rho$- mesons in wide range of momentum transfers
$Q^{2}$. At large $Q^{2}$ the obtained pion form factor asymptotics coincides
with that of QCD predictions. The method permits to perform analytic
continuation of pion form factor to complex plane of momentum transfers that is
in accordance with predictions of quantum field theory.
