Joint Use of Sum and Delta Channels for Multiple Radar Target DOA Estimation

This paper deals with the problem of estimating the parameters, i.e., complex amplitudes, directions of arrival (DOAs), and Doppler frequencies, of multiple radar targets present in the same range-azimuth resolution cell of a surveillance radar, by joint processing the sum and delta channel data. The AML-RELAX (asymptotically maximum likelihood) estimator previously derived by the authors is extended to a two-channel system scenario. Both the cases of targets having the same Doppler frequencies and different Doppler frequencies are considered. Performance is numerically investigated through Monte Carlo simulation and compared with that of the single channel estimator, which exploits knowledge of the sum antenna main beam only. Performance of the AML-RELAX estimator is also compared with that of two monopulse estimators for single and multiple target scenarios.