Root-music based direction-of-arrival estimation methods for arbitrary non-uniform arrays

Two computationally efficient high-resolution methods are proposed for direction-of-arrival (DOA) estimation in arbitrary nonuniform sensor arrays. Our first algorithm is based on the fact that the spectral MUSIC function is periodic in angle. Expanding this function using Fourier series, we reformulate the DOA estimation problem as an equivalent polynomial rooting problem. Our second approach applies the inverse Fourier transform to the so-obtained root-MUSIC polynomial to compute the null-spectrum without any polynomial rooting, using a simple line search. The proposed techniques are shown to offer substantially improved performance-to- complexity tradeoffs as compared to the existing root-MUSIC-type methods applicable to non-uniform arrays.