On subspace-based methods for frequency estimation of random amplitude sinusoidal signals

Sinusoidal signals with random time-varying amplitude show up in many signal processing applications. Amplitude modulation results in degeneracy of the signal subspace, i.e. the signal subspace corresponding to one amplitude modulated sinusoid is no longer spanned by one vector. In this paper, we propose modifications of two subspace-based techniques, namely ESPRIT and MODE for estimating the center frequency of a sinusoidal signal with random time-varying ARMA amplitude. Numerical simulations illustrate the good performance of the methods. Finally, a robustified scheme of the proposed methods is described and succesfully applied to red radar data.