Zero tracking algorithm for two-dimensional arrays with look direction constraint

Abstract

A new fast zero tracking algorithm is investigated in this paper for cancelling unknown interferences in two-dimensional adaptive arrays which employ linear constraints to preserve a desired signal coming from a certain known direction. Based on extending the definition of response zero to two-dimensional array systems and using similar updating rules as for linear zero tracking arrays (Ko et al., 1990), the algorithm has the advantages that its complexity is proportional to the array size and the asymptotic convergence speed for all the zeros are the same. Also, with the zeros tracking and giving information on source locations, the problem of incidental cancellation can be avoided by simply restricting the range of zero movements to prevent any zero from nulling the desired signal. Although the initial convergence of the algorithm may be rather erratic as in any optimisation problem with complicated performance surface, the proposed zero tracking technique does have low complexity, good asymptotic and tracking behaviour. It offers another possibility in look direction constrained jamming rejection and may be profitably combined with weight-updated-based algorithms so that the system can have the advantages of both sets of methods (Ko and Bachl, 1992). © 1998 Elsevier Science B.V. All rights reserved.