Patent ID: 6867726

Claim:
In a monopulse radar system for receiving, at a high-gain main antenna coupled to a receiver, a received signal which may be made up of a target signal, a mainlobe jammer signal, sidelobe jammer signals, and noise, said system further including an auxiliary array of low-gain sensor elements, a monopulse processor for determining angle of arrival from formed sum and difference beams in the receiver, a sidelobe canceller, and a mainlobe canceller for generating said sum and difference beams which are expressed as a product of elevation and azimuth factors for use by said monopulse processor, said system simultaneously yielding an undistorted elevation angular measurement by cancelling a mainlobe jammer with nulls in azimuth and an undistorted azimuth angular measurement by cancelling said mainlobe jammer with nulls in elevation, the method of operation comprising the steps of: nulling jammers in the sidelobes of said main antenna by adaptively weighting output signals of said auxiliary array in accordance with a covariance matrix expression and adding said weighted output signals to signals from said main antenna prior to processing by said mainlobe canceller; maintaining the mainlobe during said nulling; and cascading said multiple sidelobe canceller with said mainlobe canceller.