  This paper considers a simplified model of open quantum systems undergoing
imperfect measurements obtained via a projection filter approach. We use this
approximate filter in the feedback stabilization problem specifically in the
case of Quantum Non-Demolition (QND) measurements. The feedback design relies
on the structure of the exponential family utilized for the projection process.
We demonstrate that the introduced feedback guarantees exponential convergence
of the original filter equation toward a predefined target state, corresponding
to an eigenstate of the measurement operator.
