  The protection of the coherence of open quantum systems against the influence
of their environment is a very topical issue. A scheme is proposed here which
protects a general quantum system from the action of a set of arbitrary
uncontrolled unitary evolutions. This method draws its inspiration from ideas
of standard error-correction (ancilla adding, coding and decoding) and the
Quantum Zeno Effect. A pedagogical demonstration of our method on a simple
atomic system, namely a Rubidium isotope, is proposed.
