Direction-of-arrival estimation via twofold mode-projection

A new tensorial model is herein established for a special multi-invariant array of identically oriented ideal electromagnetic (EM) vector-sensors composed of small loops and/or short dipoles, under which a multilinear algebra based direction-of-arrival (DOA) estimation algorithm is proposed. The method provides DOA estimates (decoupled from polarization) by performing a twofold mode-projection which relies on the dual mode orthogonality of the newly defined ‘tensor’ signal-subspace and twofold mode noise-subspaces. The method can simultaneously exploit the polarization diversity and multi-invariance data structure of an EM vector-sensor array in a compact tensorial fashion, and is very competent for DOA estimation in a multipath environment. Simulation results are provided to illustrate the performance of the proposed method.