One- and two-dimensional direction-of-arrival estimation: An overview of search-free techniques

Two Uniform Linear Arrays for Non-Coherent and Coherent Sources for Two Dimensional Source Localization

“…Recently, several interesting techniques have been developed to resolve the 2D DOA estimation of multiple incoming incident sources [5][6][7][8][9][10][11][12][13][14]. However, most of these techniques are only applicable when the signals are uncorrelated.…”

“…The elevation (θ) is estimated from the Q matrix and azimuth (φ) from the R matrix. The proposed method has several advantages over the methods in [5][6][7][8][9][10][11][12][13][14][15][16]. First, the proposed method does not require spatial smoothing [3,4] which results in a reduction in the computational complexity and cost.…”

“…Second, the proposed method can estimate the DOA of coherent sources at very low signal-to-noise ratios (SNR). Third, a new antenna array configuration consisting of two uniform linear arrays is proposed to estimate the 2D DOA estimation for both coherent and highly correlated sources, whereas most of the existing antenna array configurations that have been proposed estimate the 2D DOA only for non-coherent sources [10][11][12][13][14]. Fourth, the proposed method utilizes only a single snapshot of the received data to estimate the DOA for incident sources.…”

“…Fourth, the proposed method utilizes only a single snapshot of the received data to estimate the DOA for incident sources. This significantly reduces the computational load and makes the proposed method a superior candidate for real-time implementation, whereas the methods in [5][6][7][8][9][10][11][12][13][14][15][16] require a large number of snapshots (e.g., 100 to 200) in order to produce a quality estimate. Fifth, computing the QR factorization for the data matrix using Toeplitz structure [17] in the proposed method requires only O((N + 1) 2 ) operations while calculating regular data matrix with dimension (N × N ) using the singular value decomposition (SVD) of the data matrix or the Eigen value decomposition (EVD) of the covariance matrix which have been heavily used by many existing schemes requires O(N 3 ) operations [18].…”

Two-Dimensional DOA Estimation Using Arbitrary Arrays for Massive MIMO Systems

“…However, in practical cases, the limitations of an array platform usually lead to an unrealistic choice of array geometry from some specific classes. Furthermore, nonuniform array geometries are empowered to accomplish considerably enhanced resolution performance as compared to uniform array geometries with a similar number of sensors [4].…”