“…Robust estimators of moments, such as autocovariances, include Ma and Genton (2000), Lévy-Leduc et al (2011), andChang andPolitis (2016) (see also Rousseeuw and Croux 1993), and for a review, see, for example, Dürre, Fried, and Liboschik (2015). They have been used by for example, Molinares, Reisen, and Cribari-Neto (2009) as plugin estimators for ARFIMA models (see also Reisen and Molinares 2012), by Sarnaglia, Reisen, and Lévy-Leduc (2010a) for the parameters of the periodic AR model with the Yule-Walker equation and by Bahamonde and Veiga (2016) for the GARCH (1,1). The idea of making the Kalman filter robust was originated with Masreliez and Martin (1977) and Cipra (1992) who proposed robust modifications of exponential smoothing (see also Cipra andHanzak 2011 andMahieu 2010 for a multivariate version).…”