A performance analysis of multipath direction finding with temporal smoothing

Subspace-based direction finding techniques, such as MUSIC, encounter great difficulty when the received signals on the antenna array are coherent. This problem can be solved by conventional spatial smoothing methods, which require at least 3M/2 antennas to resolve M coherent signals. A previously proposed preprocessing approach called temporal smoothing requires only M+1 antennas given M coherent signals. In this letter, a block-sampling temporal smoothing scheme is introduced, and we derive the MSE in the bearing estimation with temporal smoothing. Finally, the performance of the temporal smoothing is compared with the spatial smoothing.