Broadband Interference Tracking and Cancellation Using Adaptive Baseband Nullformer with Maximally Flat Responses at Null Directions

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 timemultiplexed 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.