Systems approach to adaptive side-lobe cancellation

An analysis of a digital/adaptive beamforming architecture consisting of a main array, and 1 to n shared auxiliary arrays formed by digital beamforming among a group of shared elements was conducted to determine the effectiveness of jamming interference suppression in the sidelobes of the main array when the jammer angle of arrival is known `a priori'. The auxiliary array outputs are combined with the main array output to cancel incoming jamming signals in the sidelobes of the main antenna. A single shared element auxiliary array can be used to cancel multiple jammers performing digital beamforming among the auxiliary array elements. With the use of peripheral sensors such as an ESM receiver, jammer angle of arrival information is used to steer the main antennas in the direction of a known target signal, and the auxiliary array in the direction of one (or more) known jamming signals. By digitally beamsteering the auxiliary array in the jammer directions, the sidelobe degradation in the main array is minimized. After steering the main and auxiliary arrays, complex weights are determined. The presence of a desired target signal in the mainbeam, along with the jamming signals in the sidelobes can result in weight contamination. This problem is avoided by adapting to the jamming in a pre-listen, receive-only mode before a radar dwell is transmitted. Sidelobe cancellation performance analysis results will be presented for the cases of narrowband and wideband steady-state jamming.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.