Improved Maximum Likelihood (IML) Spectrum Estimation: Performance Analysis

Abstract

Resolution capability of Capon's maximum likelihood (ML) has been greatly enhanced by modifying the spectral matrix such that its minimum eigen value is set to a small preassigned positive constant. Theoretical analysis of the proposed modification shows that the resolution capability for very small minimum eigenvalue approaches that of Pisarenko spectrum. Computer simulations have shown that the enhanced resolution is not at the cost of increased bias or variance in the direction of arrival (DOA) estimate of two uncorrected wavefronts incident on a short eight element array. The signal peak height in improved maximum likelihood spectrum (TML) is proportional to the actual power of each source.

Indexing terms:

• Array signal processing
• Direction of-arrival estimation