Digital phased array radar (PAR) can sample received signals at multiple phase centers, which enables digital beamforming (DBF) and can provide additional information in the spatial domain. Space-time adaptive processing (STAP) consists of designing a two-dimensional space-time filter to suppress contaminating signals through the joint use of DBF and spectral Doppler processing. This can be exploited to enhance clutter mitigation performance. We present the application of STAP to mitigate various types of clutter (e.g., airborne, cars, or wind turbines). The benefits of STAP for non-stationary clutter are shown through simulations and statistical analysis. The performance of adaptive processing is evaluated by comparing it with non-adaptive space-time processing by applying the two-dimensional Fourier transform. Finally, tradeoffs in clutter mitigation performance are studied as a function of PAR back-end architecture, comparing fully digital and subarray-based systems.

