Extension of the MUSIC approach for near field applications

The eigenstructure approach for any processing is examined for the case in which it is required to estimate not only the source location but also the relative intensity of the received signal at each sensor. The assumption of the MUSIC algorithm that any given source is observed by all sensors with known relative intensity is removed, and hence the proposed technique is useful for localizing emitters in the near field of the array and for using sensors with known phase but unknown gain pattern. The resulting method is illustrated by examples, which are also used to show that the standard MUSIC algorithm does not perform satisfactory when the assumption of known relative intensities is violated. Computer simulation results verify the statistical efficiency of the proposed procedure.