Space-time Two-dimensional Clutter Suppression Method Based on Subarray Beam Pattern Design

Airborne radar receivers that utilize subarray processing face challenges owing to the complex space-time coupling distribution caused by grating-lobe clutter. This results in multiple performance notches in the main beam, which severely affects target detection performance. To address this issue, we analyze the characteristics of grating-lobe clutter distribution in subarray processing and propose an approach for space-time clutter suppression based on the design of a receiving subarray beam pattern. Our approach leverages an overlapping subarray scheme to form wide nulls in the regions between subarrays where grating-lobe clutter is prevalent through beam pattern design. This design facilitates grating-lobe clutter pre-filtering between subarrays. Furthermore, we develop a subarray-level space-time processor that avoids the grating-lobe clutter coupling diffusion in the space-time two-dimensional plane by performing clutter pre-filtering within each subarray. This strategy enhances clutter suppression and moving-target-detection capabilities. Simulation results verify that the proposed method can remarkably improve the output signal to clutter plus noise ratio loss performance in grating-lobe clutter regions.