A signal processing technique based on spatial smoothing to estimate the direction of arrival (DOA) of incoming coherent jammers for a misaligned antenna array, where each antenna element is oriented in different directions, is investigated in this study. Because of the rank deficiency due to coherency, the conventional MUltiple SIgnal Classification (MUSIC) algorithm cannot distinguish the coherent signals despite its high resolution. For estimation of the coherent signals, the misaligned antenna array is divided into overlapping subarrays and the received model is derived by considering the misalignment. The obtained received signal model is applied to the constructed scanning vector system for finding peaks of the spatial spectrum whereas the conventional scanning vector of the existing spatial smoothing technique, which reflects only the phase difference of the received signals between the antenna elements, can undergo performance degradation due to the antenna element misalignment. For validation, a representative simulation result for comparing the performances between the proposed method and conventional spatial smoothing method is proposed.

Keywords: jammer, misaligned antenna array, MUSIC algorithm, DOA estimation, spatial smoothing