Two-dimensional chirp z-transform algorithm to the range-dependence problem for forward looking airborne radar

The clutter Doppler frequency depends on range in non-sidelooking airborne radar(non-SLAB) for Ground Moving Target Indication, which leads to a wide clutter notch in space time adaptive signal processing (STAP). According to clutter model, we propose a novel method which can transform clutter returns from space-time domain into azimuth-Doppler domain excluding elevation angle information, resulting in the identical clutter spectrum in both the mainlobe and the sidelobe. Accordingly a new space-time matrix produced by two dimensional (2-D) IFFT of the compensated spectrum can be applied for the clutter suppression through STAP. This method can be realized by 2-D Chirp z-transform (CZT) algorithm with low complexity. Simulation results show a significant improvement in processor performance.