Local polynomial approximation based beamforming for localization of rapidly moving sources

A windowed local polynomial approximation (LPA) of time-varying directions-of-arrival (DOA) is exploited to derive a new form of beamformer for source localization and tracking in highly nonstationary environments. The relationship between our LPA-beamformer and the conventional beamformer is derived. Closed-form expressions are obtained for the bias and variance of the LPA-beamformer in the nonstationary case and the problem of optimal window choice is discussed.