Abstract: The elimination of jamming signals from received radar signals is conventionally accomplished by side lobe cancellation techniques. Large interfering signals caused either by clutter or other sources, however, can cause intolerable degradation of coherent side lobe cancellation (CSLC) systems. In the present invention an inhibit signal is used to open the input to the coherent side lobe cancellation error sensing circuits thus preventing large signals from entering the coherent side lobe cancellation loop. Large signals entering coherent side lobe cancellation loops give rise to erroneous transients in the output. The invention effects storage of previously sensed error signals so as to continue jammer cancellation until new data become available to update the error signals. The inhibit signal is generated by a combination of coherent side lobe cancellation sensing circuits and logic control circuits that determine when an inhibit signal should be generated.

Abstract: The elimination of interfering radiation from received radar signals is generally accomplished by side-lobe suppression systems. Large clutter signals, however, can cause a side-lobe suppression system to become almost inoperable. In a high clutter environment the operation of a conventional side-lobe suppression system may also result in a high incidence of false alarms. In the present invention, pulse interference that arrives by way of the main antenna side-lobes that is smaller on the side-lobe suppression channel than the clutter signal appearing on the main radar channel is blanked prior to the implementation of a moving target indication (MTI) channel. A sharply rising interference pulse such as a spike occurring in the auxiliary channel may be detected by a fast time constant (FTC) circuit to provide a sidelobe blanking signal.