“…In the past three decades, numerous successful applications of the EKF have been reported in the literature, but some intractable difficulties have also been encountered. For example, the use of EKF was reported in some applications to lead to biased estimates or even divergence, due to stepwise linearization (Julier & Uhlmann, 2004;Norgaard, Poulsen, & Ravn, 2000;Romanenko & Castro, 2004), inappropriate initial state estimates (Glielmo, Setola, & Vasca, 1999;Ljung, 1979;Reif, Sonnemann, & Unbehauen, 1998), unknown covariance matrices of involved noise, or even the Gaussianity assumption of involved noise (Arulampalam, Maskell, Gordon, & Clapp, 2002;Chen, Morris, & Martin, 2005), etc. To address such problems, some other nonlinear filtering methods, especially unscented Kalman filtering (UKF) (Julier & Uhlmann, 2004) and particle filtering (PF) (Arulampalam et al, 2002), have been tested for a variety of state estimation applications, gaining increasing popularity.…”