Spatial Spectrum Estimation Direction Finding Algorithm of Uniform Linear Array Based on Virtual Array Transformation and Data Enhancement

Spatial spectrum direction finding is a kind of radio signal direction finding technology which combines multi-element antenna and multi-channel signal processing. The spatial spectrum estimation technique has been extensively utilized in both military and civilian fields in the process of continuous development of science and technology. As for the applications in military field, it makes a crucial contribution to intelligence reconnaissance and electronic countermeasures as a passive detection technique. However, if there are multiple incident signals simultaneously which are coherent or have a low signal-to-noise ratio (SNR), the direction-finding performance will degrade notably. In this paper, a direction-finding algorithm with spatial spectrum estimation for uniform linear arrays (ULAs) based on virtual arrays and data augmentation was proposed to address this problem. Firstly, a basic signal model for the direction-finding with spatial spectrum estimation was established based on the direction-finding principle; next, the conventional direction-finding algorithm was improved by utilizing the virtual array transformation, forward/backward spatial smoothing (FBSS) and data augmentation; finally, three simulation experiments were carried out for analysis and discussion of the results. The simulation findings herein demonstrated the correctness of the algorithm proposed and its adaptability to multiple coherent signals.