Adaptive filter for a linear time-varying system with a high-order estimator

In the paper, a novel adaptive filter design for a linear time-varying system is proposed. The authors introduce a robust height order estimation (HOE) to which they apply the HOE for a linear time-invariant system by using a modification and show the sufficient condition for stability. Since the robust HOE can estimate the differential of any degree, θˆ^(ρ)(t) from a parameter θ(t) directly, the number of control parameters does not increase, and all parameter vectors θˆ^(ρ)(r) can converge to an unknown vector θ^(ρ)(t) in the case of θ(r)-θ(t)=0. Furthermore, the proposed algorithm does not require the structure of unknown parameters. Finally, the system is compared to the conventional method by numerical simulation and the effectiveness is demonstrated