Frequency-DOA estimation based on subspace rotation

A new method and its modified version based on the concept of multiple invariance for simultaneous estimation of both the center frequencies and the directions-of-arrival (DOAs) of multiple narrow band signals are introduced in this paper. The new approach automatically pairs the center frequencies and DOAs by computing them directly from the eigen-decomposition of a so-called signal space-time matrix (SSTM), and circumvents the problems encountered in DOA estimation of fully correlated signals based on spatial smoothing technique. Simulation results show that the proposed method is effective.