Improved symmetric flipped nested array for mixed near‐field and far‐field non‐circular sources localization

Abstract

At present, there are few sparse arrays used in the mixed near-field (NF) and far-field (FF) localization based on non-circular (NC) signals. Inspired by the symmetric flipped nested array (SFNA) used in the existing mixed NF and FF NC source, in order to further improve the parameter estimation accuracy of the mixed NF and FF NC signal, an improved symmetric flipped nested array (ISFNA) for mixed NF and FF NC sources localization was developed. First, the uniform subarrays in the SFNA are rearranged, ⌈ N 2 2⌉ − 1 elements are extracted from the uniform subarrays and rearranged into ISFNA. ISFNA is more sparse, the array aperture is larger, and the array degree of freedom (DOF) is higher; second, the formula of the maximum consecutive lags of ISFNA is given; third, a special fourth-order cumulant is used to eliminate the range parameter and then use a one-dimensional (1-D) spectral peak search to obtain all Directions of Arrival (DOAs). By defining the range search, the range can be obtained by bringing in estimated DOAs. Finally, the superiority of the proposed array is proved by simulation.

Localization of mixed‐field sources based on fourth‐order cumulant matrix rank reduction

“…The eigenvalue decomposition is performed on the matrix C x . The eigenvalues are arranged from largest to smallest as γ 1 , γ 2 , …,γ (2L+1) 2 , and the corresponding eigenvectors are e 1 , e 2 , …, e (2L+1) 2 . The eigenvectors that correspond to the K large eigenvalues from cumulant matrix C x are tensed into the signal subspace E s = [e 1 , e 2 , .…”

“…Introduction: Source localization is a crucial research direction in the fields of sonar, radar and mobile communications [1][2][3]. With the continuous expansion of antenna arrays, the localization problem of mixedfield sources where far-field (FF) sources coexist with near-field (NF) sources is one of the urgent difficulties in the area of array signal processing [4,5].…”

A Novel Low-Complexity Method for Near-Field Sources Based on an S-IMISC Array Model

“…From Formula (30), we see that the distance of the first subspace is the shortest, so during the simulations, we generally select subspace 1 for the spectral peak search. There is a certain relationship between these types of distance information, i.e., their reciprocal obeys uniform distribution, and thus, they can be converted by Formula (31). Therefore, we do not need to search spectral peaks in the whole Fresnel region but only in a certain region to obtain the distance information and use the conversion relationship between the distance information to calculate the other distance information using Formula (31).…”

“…Wang et al [29] proposed an enhanced symmetric nested array model (ESNA) for mixed-signal parameters. Wang et al [30,31] proposed a novel symmetric flipped nested array (SFNA) and an improved symmetric flipped nested array (ISFNA) for mixed-signal parameter estimation. The above im-proved nested array models can achieve higher DOF.…”