Direction-of-arrival estimation for narrow band coherent and incoherent sources in the presence of unknown noise fields

A solution is presented to the general multiple source location problem in which the sources are incoherent, partially coherent, or coherent narrowband plane waves contaminated by unknown noise at the sensor terminal. The method provides the required source azimuth and elevation angle estimates, and the array´s geometry is diversified. The method is based on computing the difference of the subarray covariances, thus subtracting the unknown noise covariance and leaving only the difference matrix of the signal covariances with respect to two subarrays. Arranging the main array appropriately could compensate for the deficiency of rank of covariance due to the coherent sources (which makes the MUSIC method invalid)