VSS observer for linear time varying system

The problem of designing an observer for state estimation using variable structure system (VSS) theory is discussed. The theory and design principles for linear time-varying systems are presented. The observer is constructed by introducing a block-observable from which is similar to a lower triangular matrix. The convergence of the observer is guaranteed by a sliding mode with first-order filter. Simulation results show that the proposed observer is able to provide correct estimated values of the states