Robust frequency estimation

A robust estimation method for frequencies of received signals is investigated. The received signals are represented as the sum of sinusoidal signals and an additive noise process. The additive noise is assumed to be a mixture of a Gaussian and an outlier process. The influence function of a robust estimate is derived for time-varying (sinusoidal) signals. The variance of the robust estimate is also derived, using the influence function, and found to be close to both the Cramer-Rao lower bounds, one of which is computed under the perfect Gaussian assumption and the other under the contaminated Gaussian assumption. It is proved that the robust estimate possesses high-resolution properties even when outliers exist