In this paper, a parallel pre-filtering scheme is presented to address the problem of estimating the parameters of a sinusoidal signal from biased and noisy measurements. Extending some recent result on pre-filtering-based frequency estimators, a parallel pre-filtering scheme is proposed to deal with the unknown offset and bounded measurement perturbations, which are typically present in several practical applications. A simple frequency estimator, having parallel second-order pre-filters, is introduced. The behaviour of the proposed algorithm with respect to bounded additive disturbances is characterized by Input-to-State Stability arguments. Numerical examples shows the effectiveness of the proposed technique.
