Bearing estimation in a colored noise background using the method of multiple windows

D.J. Thomson's method of multiple-windows (see Proc. IEEE, vol.70, p.1055-96, 1982) is applied to the problem of bearing (angle-of-arrival) estimation, at low grazing angles, in the combined presence of specular and diffuse multipath. The specular multipath component is coherently related to the direct signal component, both within a beamwidth of each other. They are modeled as line components in the wavenumber spectrum. The diffuse multipath component provides a colored noise background that is correlated to some extent with the line components. The estimator is tested with experimental data, collected by means of a 32-element sampled aperture antenna system operating at X-band over a lake surface. Additional improvement is observed when multiple frequencies and prior information is incorporated in the estimator.<>