A further optimisation of adaptive subspace-based frequency estimation for multiple real valued sine waves is considered in this paper. Authors proposed in [10] a novel combination of strong adaptive covariance matrix update and optimised block processing for frequency values retrieval. The new optimised approach combines the projection approximation subspace tracking technique based on deflation PASTd (for the signal subspace update) with the ESPRIT-like frequency estimation of real-valued sinusoids (for frequency values retrieval). Consequently, a new adaptive subspacetracking algorithm for frequency estimation is proposed. The method proposed brings a significant reduction in arithmetical complexity at the same level of accuracy.

Keywords: Subspace tracking, Frequency estimation, Real-valued data, R-ESPRIT, PASTd.