DOA estimation of wideband sources using a harmonic source model and uniform linear array

We consider here the problem of estimation of DOA's of multiple wideband so urces incident on a uniform linear array (ULA) in the presence of spatially and temporally white Gaussian noise (WGN), The approach presented here bui lds up on the IQML algorithm suggested by Bresler and Macovski for the case of narrowband DOA estimation. It is shown that the concept of ARMA model f or the observed data vector for the narrowband case can be generalized to m odel an appropriately stacked, space-time data vector obtained by combining the Spacetime samples. The coefficients of the corresponding 2-D predictor polynomial can be used to represent the null subspace of the wideband arra y steering matrix, and rooting of the polynomial at each frequency, separat ely, gives the DOA estimates, These separate estimates at multiple frequenc ies are combined into a single DOA estimate in a least squares sense. This leads to the formulation of an IQML-like procedure for the spatial paramete r estimation of wideband sources. Like its narrowband counterpart, the prop osed approach is applicable to both noncoherent and coherent sources, The p erformance of the proposed method is studied via extensive computer simulat ions and by comparison with the CR bounds.