Non-circular signals for nested array: sum–difference co-array and direction of arrival estimation algorithm

• Published in: IET radar, sonar & navigation Vol. 14; no. 1; pp. 27 - 35
• Main Authors: Yunfei, Wang, Jinqing, Shen, Xiaofei, Zhang, Yi, He, Xiangrui, Dai
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 01.01.2020
• Subjects: array signal processing; co‐array algorithm; co‐array aperture; direction of arrival estimation; DOA estimation algorithm; enhanced degrees of freedom; enlarged array aperture; MUSIC algorithm; nested array; noncircular signals; reduced‐dimension multiple signals classification; Research Article; SD‐RD‐MUSIC co‐array algorithm; signal classification; sum co‐array; sum–difference co‐array; two‐dimensional spectral search; typical difference co‐array; enhanced degrees of freedom; sum co-array; reduced-dimension multiple signals classification; direction-of-arrival estimation; sum–difference co-array; MUSIC algorithm; nested array; enlarged array aperture; signal classification; SD-RD-MUSIC co-array algorithm; typical difference co-array; noncircular signals; co-array aperture; direction of arrival estimation; co-array algorithm; array signal processing; DOA estimation algorithm; two-dimensional spectral search
• ISSN: 1751-8784; 1751-8792; 1751-8792
• DOI: 10.1049/iet-rsn.2019.0111

Nested array has aroused remarkable attention due to the capability to obtain both enhanced degrees of freedom (DOFs) and enlarged array aperture, whereas only difference co-array is employed. Here, the authors construct the sum co-array of nested array by utilising the non-circular (NC) characteristic and, subsequently, the sum–difference (SD) co-array is obtained by careful crafting of the sum co-array and the typical difference co-array, which doubles the resulting co-array aperture and, simultaneously, further increases the achievable DOF compared with the difference co-array of nested array. Moreover, to circumvent the time-consuming two-dimensional spectral search, the authors proposed the reduced-dimension multiple signals classification (MUSIC) algorithm with the SD (SD-RD-MUSIC) co-array of the nested array by discarding the NC phase. Resultantly, the proposed SD-RD-MUSIC co-array algorithm can resolve more signals and obtain more accurate direction of arrival estimates. In addition, the effectiveness and superiority of the proposed method are validated by numerical simulations.