“…The zero‐mean white noise vector
represents modeling error. It should be emphasized that unlike Equation () that is expressed in terms of
, in the derivation of GDFs (Gillijns & De Moor,
2007a,
2007b), the process equation was formulated by choosing a different approximation of input with a ZOH assumption, that is,
, leading to
, wherein the input in the process equation lags one step behind the input in the observation equation.…”