Simple Nullformer for Adaptive Interference Tracking and Cancellation in Broadband Applications Using Linear Antenna Array

A new algorithm for the tracking and cancellation of broadband sources in linear arrays employing baseband tapped delay line processing is presented and investigated. Using this technique, each broadband source is individually tracked in a cyclical time-multiplexed manner by steering a broadband null formed from the use of a tapped delay line filter with weights constrained to have maximally flat frequency response at the nulling direction. Since the new algorithm updates only one tapped delay line filter at any instant, the overall implementation complexity of the proposed algorithm is comparable to that of using the LMS algorithm directly on a broadband array. However, unlike the latter algorithm, the convergence behaviour of the new algorithm is significantly faster and is almost independent of the external noise environment.