Propeller-Modulation Clutter Suppression for Airborne Radar Based on 3D Sliding Window and Orthogonal Projection

For non-side looking airborne radar (NSLAR), when the main lobe beam of the antenna passes through a turboprop engine, propeller-modulation clutter is generated. This expands the clutter Doppler spectrum and increases clutter’s non-stationarity, reducing Space Time Adaptive Processing (STAP) performance. To address this issue, a novel propeller-modulation clutter suppression method is proposed. Firstly, this method uses a blocking matrix and three-dimensional (3D) sliding window processing to generate more training samples. These samples are then used to estimate the clutter covariance matrix (CCM) of the sub-aperture data. Next, the echo data of the cell under test (CUT) is subjected to 3D sliding window processing to obtain sub-aperture data of echo. Finally, the non-stationary propeller-modulated clutter at near-range is suppressed using orthogonal projection (OP) of subaperture. Simulation results demonstrate that the proposed method effectively suppresses propeller-modulation clutter.