ZERO TRACKING ALGORITHM FOR 2-DIMENSIONAL ARRAYS WITH LOOK DIRECTION CONSTRAINT

A new fast zero tracking algorithm is investigated in this paper for c ancelling unknown interferences in two-dimensional adaptive arrays whi ch employ linear constraints to preserve a desired signal coming from a certain known direction. Based on extending the definition of respon se zero to two-dimensional array systems and using similar updating ru les as for linear zero tracking arrays (Ko et al., 1990), the algorith m has the advantages that its complexity is proportional to the array size and the asymptotic convergence speed for all the zeros are the sa me. Also, with the zeros tracking and giving information on source loc ations, the problem of incidental cancellation can be avoided by simpl y restricting the range of zero movements to prevent any zero from nul ling the desired signal. Although the initial convergence of the algor ithm may be rather erratic as in any optimisation problem with complic ated performance surface, the proposed zero tracking technique does ha ve low complexity, good asymptotic and tracking behaviour. It offers a nother possibility in look direction constrained jamming rejection and may be profitably combined with weight-updated-based algorithms so th at the system can have the advantages of both sets of methods (Ko and Bachl, 1992). (C) 1998 Elsevier Science B.V. All rights reserved.