Abstract: A two-way coded aperture radar imaging system is disclosed. The system includes an antenna reflector and a radar signal transceiver configured to generate sequential radar transmission signals and receive a plurality of respective reflected radar signals. The system also includes a phase control component configured to phase-encode the sequential radar transmission signals via a plurality of phase-codes to generate a respective plurality of phase-coded radar pulses that are concurrently reflected at a respective plurality of sub-aperture portions of the antenna reflector to concurrently transmit the plurality of phase-coded radar pulses from the antenna reflector to a target. The transmitted phase-coded radar pulses can be reflected from the target as the respective plurality of reflected radar signals.

Abstract: A synthetic aperture radar (SAR) which operates at UHF frequencies and which includes a two element antenna. The SAR generates a null in the backlobe of the antenna pattern at the location of a target which is steered rather than trying to obtain directivity in the mainlobe. Both analog and digital implementations are provided. In the analog approach, required phase shifts are performed at a frequency higher than the RF output frequency and the receive and transmit nulls are steered separately to increase the width of the null so as to allow for wider SAR swaths. The digital implementation involves steering the null only on receive and multiplying fast time samples by a complex phase correction similar to that used in the analog approach to form the beam. The phase correction is also performed prior to range resolution which employs "stretch" processing, so as to achieve high range resolution.

Abstract: The present invention includes an apparatus that prebiases a transmitted radar signal. The prebiasing of the transmit signal automatically aligns the return signals in one dimension or dimensionally transforms the return signals thereby removing the need for one of the dimensional processing operations of a conventinal two dimensional return signal interpolator. A map function generator produces small frequency (phase) changes in the transmitted signal during each pulse over the entire integration or exposure period. The map function generator produces a parabolic frequency change control signal applied during the integration period. The control signal is divided into segments where each segment controls a single transmit pulse. The control signal modifies a linear frequency modulation control signal. conventionally produced by high resolution radar systems.