Title: Partial-order reduction of observers for linear systems
Abstract: Full-state observers for linear systems use available measurements for the estimation of the entire state of a system. Reduced-order observers instead deliver an estimate only in the unmeasured state subspace while the state values in the measured subspace are taken directly from the measurements. This paper presents a combination of both types of observers which directly uses only part of the measured subspace and estimates/filters the rest of the state space. The order of this new observer is freely selectable between that of the full-state observer and of the reduced-order observer. A practical example demonstrates the validity of the new observer form. The results show that the performance of a state-feedback controller with the new observer is similar to that with the full-state observer.