A simple, fast adaptive algorithm for broad-band null steering arrays

Abstract

A simple algorithm for adaptively steering the broadband null in a two-element power inversion array which uses a tapped delay line filter as the processing element is presented and investigated. By performing a simple signal transformation, the algorithm constrains some of the filter weights so that a variable length delay line is approximated in the maximally flat sense. By using the least mean square (LMS) algorithm to adjust the weights controlling the length and gain of the delay line, a broadband null is then adaptively formed to track and reject the broadband jammer. As studied analytically and by using simulation results, the convergence behavior of the algorithm is fast and depends only on the tolerable level of misadjustment noise. Its implementation complexity is comparable to that of using the LMS algorithm directly.