Non-parametric techniques for the estimation of spatial spectra in non-stationary environments

A novel approach to the problem of estimating a spatial spectrum in a non-stationary environment has been presented. The approach adopted relies on the same principle as that which underpins the Wigner distribution. The proposed methodology results in the construction of a new sufficient statistic that can be used in conjunction with a variety of existing array-processing techniques. The resulting schemes are shown to be robust to source motions. Some of the limitations of this approach have been discussed and how they can be overcome is demonstrated.