Efficient estimation of closely spaced sinusoidal frequencies using subspace-based methods

Both experience and analysis show that the widely used subspace methods, such as MUSIC and ESPRIT, perform poorly when applied to estimate closely spaced sinusoidal frequencies. This severely limits the resolution of subspace methods for frequency estimation. In this letter, we present a simple interleaving technique that significantly improves the performance of subspace based methods in the case of closely spaced frequencies. Simulation results show that the improved performance is comparable to the corresponding Cramer-Rao bound (CRB).