A space-time beam-space ML algorithm for low-angle tracking

In this paper, a modified space-time beam-space ML (STBSML) direction-of-arrival (DOA) algorithm is presented for low-angle tracking. The STBSML algorithm can precisely estimate the direct angle and the reflected angle of low-altitude targets, which is robust to small snapshots and low SNR by the temporal and spatial signal formation. The algorithm's computation load is reduced by beam-space transformation. Theoretical analysis and numerical simulations illustrate that the STBSML algorithm outperforms the conventional ML method, and hence is available for VHF array radar applications.