An improved mode-music algorithm for DOA estimation of coherent sources based on hybrid array

Mode space algorithm is capable of estimating the DOA for coherent sources provided that the receiving array is uniform circular array (UCA). In this paper, we propose an improved mode-MUSIC (IMODE-MUSIC) algorithm based on a hybrid array which is composed of a uniform circular array and a directional antenna located at the circular array center. By utilizing the mode space algorithm, the UCA is transformed into the uniform linear array (ULA). A Toeplitz matrix is constructed by using the second order of the output data received from the ULA and the directional antenna. After revising this Toeplitz matrix, MUSIC method is applied to get the DOA estimation of the coherent sources. The proposed method has better resolution ability and accuracy than MODE-MUSIC. Moreover, the IMODE-MUSIC is still valid when the number of sources is more than the number of array elements. We prove the IMODE-MUSIC method both theoretically and numerically.