Dominant mode power spectrum estimation

The minimum variance, distortion less response (MVDR) and maximum entropy method (MEM) high resolution power spectrum estimators are decomposed in terms of the dominant orthogonal modes of the covariance matrix of the analyzed data. From these decompositions, the individual orthogonal modes of the spectrum can be enhanced with the effect of increased resolution of the spectral components of the spectrum. As an example, the problem of estimating the range of a radiating source from a line array of receivers is considered. It is demonstrated that, in the presence of uncorrelated noise only, the variance of the frequency (range) estimator for a single source is essentially the same for all techniques but that range resolution can be dramatically improved with the modal techniques.