Evaluation of aggregation techniques for DOA estimation of wideband radar signals

This paper analyses the performance of two incoherent aggregation techniques for direction of arrival (DOA) estimation of linear frequency modulated (LFM) radar signals. The aim is to determine suitable aggregation techniques for blind DOA estimation aimed for real-time and wideband implementation. The first technique combines the spatial pseudospectra calculated from the spatial covariance matrix (SCM) of the signal present in each of the frequency bins obtained after frequency channelization. The second technique directly combines the spatial covariance matrices (SCMs) from each of the frequency bins before calculating a single pseudospectrum. The aim is to determine suitable aggregation techniques for blind DOA estimation for real-time implementation. First, we compare the DOA estimation performance of incoherent SCM-based aggregation with incoherent spatial pseudospectra-based aggregation. Secondly, we determine the types of signals and conditions for which these incoherent aggregation techniques are suitable. Finally, we demonstrate that the low-complexity SCM-based aggregation technique can achieve relatively good estimation performance under certain conditions. The two incoherent aggregation techniques discussed, thus offer a computationally efficient way in comparison to coherent processing techniques.