Space time adaptive processing for domain factorised element-digitised array radar

Due to limitations of current radar system hardware, digitisation and adaptive beamforming are usually performed at the subarray level of large phased array radar. In the long term, technology will permit development of element digitised array radar (EDAR), although this may not necessarily lead to adaptive processing being performed at the element level. The large computational requirements for adaptive processing, which vary with the cubed power of the number of digital channels, and the large data training set required, will restrict the number of digital channels employed. However, with element digitisation we are free to choose arbitrary degrees of freedom (DOF) reduction schemes to maximise adaptive beamformer performance. It has already been shown that DOF reduction schemes using domain factorisation (DF) give performance advantages in high clutter airborne intercept (AI) environments. We extend the DF technique described by Paine (see IEE Proceedings Radar, Sonar & Navigation, vol.148, no.2, p.81-88, 2001) to space-time adaptive processing (STAP) and demonstrate the detection of slow moving targets that are ambiguous with main beam and strong nadir clutter.