Integrated adaptive nulling/DPCA processing for a moving look-down radar

It is shown that both clutter and interference sources may be cancelled in a moving look-down radar which incorporates an adaptive array antenna. This is achieved by combining displaced phase centre antenna (DPCA) processing with adaptive nulling. Two integrated structures, the fixed processor and combined adaptive processor are investigated. For equivalent numbers of adaptive degrees of freedom, these are shown to give comparable levels of cancellation performance as nonideal effects increase in severity. In the case of the fixed DPCA processor the ability to cancel clutter in the presence of nonideal behaviour was unexpected. However, it is shown that this behaviour interacts with the fixed DPCA processing in such a way that reasonable levels of clutter cancellation may be maintained