Multiple emitters localization by UAV with nested linear array: System scheme and 2D-DOA estimation algorithm

Unmanned Aerial Vehicle (UAV) equipped with uniform linear array has been applied to multiple emitters localization. Meanwhile, nested linear array enables to enhance localization resolution and achieve under-determined Direction of Arrival (DOA) estimation. In this paper, we propose a new system structure for emitters localization that combines the UAV with nested linear array, which is capable of significantly increasing the positioning accuracy of interested targets. Specifically, a localization scheme is designed to obtain the paired two-dimensional DOA (2D-DOA, i.e. azimuth and elevation angles) estimates of emitters by nested linear array with UAV. Furthermore, we propose an improved DOA estimation algorithm for emitters localization that utilizes Discrete Fourier Transform (DFT) method to obtain coarse DOA estimates, subsequently, achieve the fine DOA estimates by sparse representation. The proposed algorithm has lower computational complexity because the coarse DOA estimates enable to shrink the range of over-complete dictionary of sparse representation. In addition, compared to traditional uniform linear array, improved 2D-DOA estimation performance of emitters can be obtained with a nested linear array. Extensive simulation results testify the effectiveness of the proposed method.