Direct Position Determination for Multiple Signals Without Prior Knowledge of Source Number

Source localization by distributed base stations has been an essential aspect in various applications across both civilian and military surveillance systems. In this letter, we propose a direct position determination (DPD) method based on a set of joint spatio-temporal correlation matrices. The proposed technique is applicable to multiple targets without requiring the prior knowledge of source number. We first establish a signal model intercepted by multiple base stations with direction of arrival (DOA). These signals are utilized to calculate several spatio-temporal correlation matrices exhibiting a joint diagonalization structure. Thereafter, we adopt the correlation matrices to formulate the DPD cost function, thereby enabling the simultaneous estimation of both source positions and their number from a spatial spectrum. In addition, several simulations are conducted to demonstrate the effectiveness of the proposed method. Numerical results indicate that the proposed approach achieves comparable localization accuracy to that of traditional methods under high signal-to-noise ratio (SNR) conditions, while outperforming them at low SNRs. Moreover, it demonstrates superior resolution capability in multi-source scenarios due to the incorporation of joint spatio-temporal information.