Use of antenna nulling with frequency-hopping against the followerjammer

Antenna nulling is an effective ECCM (electronic counter countermeasures) asset that can be put in use with other ECCM techniques to obtain additional processing gain. Two antenna nulling schemes that can be used with frequency hopping to reduce the follower jammer threat are described. One of the schemes is only effective with uncorrelated signals. The second scheme is designed for coping with correlated jamming. Both schemes capitalize on the arrival time differences of the desired signal and the interference to isolate the interference for cancellation. The fast converging sample matrix inversion algorithm is considered in both schemes for improved effectiveness. The performance of the antenna nulling schemes, described in terms of the array output-signal-to-interference and noise ratio (OSINR), is evaluated by computer simulation. The OSINR of the array at a single frequency in the hop-set is presented for a range of desired signal-to-noise and jammer-to-noise ratios. The processing gain offered by the antenna nulling system was found to increase with increasing desired signal-to-noise ratio