Abstract: A displaced-phase-center antenna technique which compensates accurately for he motion of an airborne radar system in both the boresight direction of the antenna and in the direction normal to the boresight. An antenna system comprising a broadside array of endfire arrays forms four receive beams which are displaced from each other in both the boresight direction and in the direction normal to the boresight. These four beams are used to produce signals which correspond to signals from two receive beams with phase centers having a separation equal in magnitude and direction to the aircraft's motion during the interpulse period. A signal scattered from a fixed object on a first transmitted pulse and received in one of the two receive beams will have the same phase characteristic as a signal scattered from the same fixed object on a subsequent pulse and received in the other receive beam. Upon proper delay of the first received signal, the returns from the fixed object may be cancelled.

Abstract: The effects of simultaneous platform motion and antenna scanning are compated for in radar systems of the moving-target-indicator type. Signals from auxiliary sub-arrays of the antenna compensate signals from main sub-arrays of the antenna for the effects of antenna scanning. Delayed, scanning-compensated signals from the main sub-arrays are then combined with undelayed, uncompensated signals from the main sub-arrays to provide signals that are compensated for the effects of scanning motion and platform motion. A first embodiment provides a clutter canceller having motion compensation at each stage of cancellation. A second embodiment provides a large number (N) of motion-compensated signals which are synchronized in time and phase for further MTI processing.

Abstract: The effects of platform motion or antenna scanning in radar systems of the oving-target-indicator type are compensated for by arrangements which use difference-channel signals to correct sum-channel signals for the changes in phase and amplitude of the backscattered sum-channel signals due to the platform motion and antenna scanning, respectively. Clutter-canceller arrangements having motion compensation at each stage of cancellation and an arrangement for providing a large number (N) of motion-compensated signals which are synchronized in time and phase are shown.