Four-channel monopulse for main beam nulling and tracking

A three-channel monopulse system consisting of the sum, delta alpha, and delta beta channels is used to angle-track detected targets in most phased array radar. The addition of a fourth monopulse channel can provide nulling of main beam jammers to significantly improve the detectability of targets that are within a beamwidth of the jammer. In addition to improved detectability, it is also possible to track targets in angle in the presence of main beam jamming using this technique.