  This work addresses the problem of distributed formation tracking for a group
of follower holonomic mobile robots around a reference signal. The reference
signal is comprised of the geometric center of the positions of multiple
leaders. This work's main contribution is a novel Modulated Distributed Virtual
Observer (MDVO) for the reference signal. Moreover, the proposed MDVO is based
on an exact dynamic consensus algorithm with a prescribed convergence time. In
addition, we provide simulation examples showcasing two different application
scenarios for the proposal.
