Abstract: A beamforming adaptive control loop is simultaneously employed in combination with a null-steering adaptive control loop to enhance the signal/interference ratio resulting in an increase in the message quality. The loops employ spectral processing in which case bandpass filters and notch filters form separate loops which enhance the desired signals and cancel the undesired signals, respectively. The correlated output from the beamforming loop is added to the correlated output of the null-steering loop and mixed with the incoming signal.

Abstract: An adaptive signal processing system for enhancing the signal-to-interfere characteristics on both receive and transmit, using an in-phase quadrature correlator to control phase and amplitude adjust circuits located in the antenna signal paths. To increase the dynamic range, automatic gain control circuits are included in the reference and feedback signal paths to the correlator.

Abstract: Multiple interference signals in an electromagnetic wave communication system are individually discriminated against by a beamport sidelobe canceller comprising a multichannel auxiliary system in which spatial filtering of the angular sectors of interest is performed prior to sidelobe cancellation. Each spatial filter of the auxiliary system has its own adaptive control and only those interfering signals appearing in its assigned sector are operated on by that loop. The output of the main communication system receiver is summed with the outputs of the auxiliary system channels to produce a system output and an adaptive control loop feedback signal. The feedback signal initiates the generation of a cancellation signal in any adaptive control loop in which correlation of interference signals occur in both the main communication system received signal and the signal received by the auxiliary system channel to which that loop is connected.

Abstract: A multilevel sidelobe canceller utilizes power level sensitive processing of the auxiliary array outputs to adaptively spatially filter multiple jamming signals with an additional level of adaptive loops prior to conventional sidelobe cancellation.