Bearing estimation of coherent sources by circular spatial modulation averaging (CSMA) technique

Application of antenna arrays to mobile communications. II. Beam-forming and direction-of-arrival considerations

“…Some other preprocessing schemes to decorrelate the correlated sources include random permutation [414], mechanical movement using a circular disk [422], construction of a preprocessing matrix using approximate knowledge of a DOA estimate [423], signal subspace transformation in the spatial domain [424], unitary transformation method [425], and methods based on aperture interpolations [415], [426], [427].…”

“…Ideally, in the absence of correlation, the array correlation matrix for a uniformly spaced linear array has a Toeplitz structure, that is, elements of the matrix along each diagonal are equal, and the estimated matrix by the spatial smoothing scheme is not the closest to the Toeplitz matrix. This is done by a spatial averaging technique [420], [422], which weighs each subarray matrix differently and then optimizes the weights such that it minimizes the MSE between the weighted matrix and a Toeplitz matrix. The system that results from using this matrix to estimate the weights of the beam former reduces more interference than that given by the use of a uniform weighted matrix estimate.…”

Adaptive processing for beamforming with coherent interference using uniform circular arrays

“…As a result, some compromises in terms of the size of the virtual array are required. In contrast, the CSMA technique of [17] employs a rotating circular array. The incident signal at each array element is sampled within an angular region where the curvature of the circular array is assumed to be linear.…”