We propose a formation control strategy based on distributed position estimation for single-integrator modeled agents by using relative position measurements. Under the proposed strategy, the estimated and the actual formations globally exponentially converge to the actual and the desired formations, respectively, up to translation, if and only if the interaction graph for the agents has a spanning tree. A sufficient condition is provided for the case that the edge weights of the interaction graph are time-varying. Further, the proposed strategy is applied to formation control of unicycle-like agents.