Observer design for descriptor systems with unmeasurable disturbances

A reduced-order observer for descriptor systems subject to unmeasurable inputs is studied. The problem is formulated in terms of a constrained Sylvester equation. Solutions to such an equation completely characterize the desired reduced-order observer. Constructive necessary and sufficient conditions, which lead to a simple and easy-to-implement algorithm, are presented. It is shown how the presence of transmission zeros influences the convergence of the observer.<<ETX>>