Identification of State Space Systems in Closed Loop

The closed loop identification problem is formulated for coupled state space systems using a joint input/output approach. The identification method and the identifiability results follow a two step approach: stochastic realization of the joint input/output model, and separation of the state space into a forward and a feedback path. The paper focuses on structural identifiability conditions for the full rank case. An outline is given of the identifiability problem and its solution under more general conditions.