Evaluation of antenna architectures for angle estimation of endo-clutter targets in airborne adaptive radars

Adaptive beamforming techniques such as space-time adaptive processing (STAP) combine spatial and temporal degrees of freedom to detect slow moving targets in strong clutter backgrounds. Many techniques exist for choosing the spatial and temporal degrees of freedom. In general these techniques are typically evaluated based on their ability to provide good target detection performance using performance metrics such as signal to interference plus noise ratio (SINR). Since adaptive radars must also provide target location information it is important to also consider how the choice of spatial degrees of freedom will impact direction-of-arrival estimation performance. This paper will investigate the DoA estimation performance of various airborne array architectures including elements and fixed beams (beamspace). It will be shown that in some interference scenarios the spatial degrees of freedom required for good detection performance differ from those required for good DoA estimation performance.