Analysis of enhanced covariance matrix technique for source direction estimation in non-coherent and coherent signal environment

The performance of the enhanced covariance matrix technique (ECMT), which permits a substantial improvement in resolving the incident direction of noncoherent and coherent signals, is analyzed. It is found that the ECMT technique can achieve arbitrarily high resolution in resolving low signal-to-noise ratio (SNR) and closely spaced signals. The technique involves the suppression of the noise eigenvalue in the signal subspace covariance matrix, which results in the enhancement of the resolution and SNR output of the array processor. The signal covariance matrix is then decomposed to resolve the direction of arrival of the incident sources