Unbiased source estimation with an adaptive null steering algorithm

Abstract

A new algorithm for zero tracking is proposed and investigated in this paper. The zeros of the adaptive array, which correspond to the sources' locations, are updated recursively taking into account the effect of receiver noise so that the source parameters can be estimated in an unbiased manner. A formula relating the variances of the sources' locations to the number of samples used has been obtained, allowing the accuracy of the estimated source locations to be controlled. Since the estimates of the sources' locations are unbiased, the new algorithm has a much better performance for locating weak sources in difficult signal environments when compared with conventional methods such as simple null steering or the LMS algorithms. While the new algorithm has roughly the same implementation complexity as the LMS algorithm, it also has a better convergence behaviour than the latter algorithm. © 1993.