High resolution spatial spectrum estimation in a non-stationary environment

The computation of time-bearing representations within the context of passive sonar is considered. A novel approach to dealing with sources whose relative bearing varies as a function of time is proposed. The methodology adopted is based on ideas borrowed from the field of time-frequency analysis. The techniques presented can be applied in conjunction with a range of existing spatial spectral estimation algorithms. Some of the problems inherent in this formulation are highlighted. Simulations are used to show the utility of this approach. It is demonstrated that when the source is in motion this approach yields bearing estimates with smaller variances than can be achieved using conventional techniques.