An Improved Spatial Smoothing Technique: An Improved Spatial Smoothing Technique

Spatial smoothing techniques are effective to estimate the directions of coherent arrivals. The performance of these techniques deteriorates rapidly as the coherent arrivals become closely spaced. In this correspondence, an improved spatial smoothing technique is proposed. The algorithm makes cross-correlation of all auto-correlation matrixes of subarray output, and then takes the spatial spectrum estimation to the equivalent spatial smoothing matrix after the forward and backward correlation matrixes averaged. The formula for the algorithm is derived, and the performance of the algorithm is also analyzed. Simulation results demonstrate that the improved algorithm possesses a better resolving ability and a lower SNR threshold than conventional SS technique and subarray-covariance SS technique for DOA estimation of coherent signals.