Unknown Input observer Design for pitch motion state space

we are mainly interested in applying UIO for a third order state space system representing the pitch motion for fixed-wing plane

The idea behind UIO design is to decouple the effect of the unknown inputs (UI) from the state estimation error dynamics and to estimate asymptotically the states of the system even in the presence of unknown inputs. These UI can represent faults, disturbances or neglected dynamics in the system while modeling. This type of observers can be used in decoupling control, fault estimation, fault tolerant control.