Design of observers for descriptor systems with delayed state and unknown inputs

This note deals with the problem of full-order observers design for a class of linear descriptor systems with delayed state and unknown inputs (UI). The objectives are twofold. Firstly, the design of a full-order unknown input observer for descriptor systems with delays is studied. Secondly, if disturbance rejection is not possible, an H/sub /spl infin// observer for such systems is proposed. The existence conditions of these observers are given and proved. An illustrative example is included.