“…[2,8,14,15,17,18,23,29,32,35] and the references therein. Commonly, the H ∞ filtering theory aims at designing a filter such that the H ∞ norm of the transfer function from the noise to the filtering error is not larger than a desired noise attenuation level [3,7,11]. Compared with the popular Kalman filtering approach, the H ∞ filtering method can be utilized to effectively improve the insensitivity against parameter uncertainties and external noises without the knowledge of their statistics.…”