A new method for two-dimensional array signal processing in unknown noise environments

This paper deals with the application of the so-called 'propagator' approach to perform two-dimensional (2-D) spatial-spectrum estimation in unknown noise environments. On the assumption that the noise correlation is spatially limited, the effects of unknown noise are eliminated by using two subarrays separated far enough, and no constrained modelling of the noise field is required. In the approach, the noise subspace is estimated by using a linear operator extracted from the cross-covariance matrix of the two subarrays through a least-squares (LS) process, and the multiple source directions of arrival (DOA) are estimated without any eigendecomposition. All these properties of the approach make real-time implementation possible.