This paper presents a new polarization sensitive array composed of a two-level nested subarray and an optimallynested subarray with orthogonal oriented antennas, and then proposes a correlation matrix reconstruction ...
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This paper presents a new polarization sensitive array composed of a two-level nested subarray and an optimallynested subarray with orthogonal oriented antennas, and then proposes a correlation matrix reconstruction based estimation method for direction of arrival (DOA) and polarization state. The optimally nested array with $N$ antennas can provide maximum degrees of freedom (DOF) of difference co-array (i.e., $(N - 1)N + 1$ ), which increases the aperture of the proposed array. However, both the difference co-arrays of the optimallynested subarray and between subarrays are nonuniform linear arrays (i.e., holes appear), and hence most existing methods fall to use all information received from the proposed array, resulting in estimation performance loss. Depending on the oblique projection (OP) operator constructed by initial DOAs from the two-level nested subarray, the proposed method first fills the holes to generate the virtual correlation matrix with increased DOF. Then the DOA and polarization state are estimated efficiently. The resulting DOAs can be regarded as the new initial angles for OP operator construction, to iterate aforesaid steps for estimation performance enhancement. The Cramr-Rao bound (CRB) and the computational complexity of the proposed method are provided. Simulation results are given to validate the effectiveness of the proposed array and the proposed method.
To obtain a large aperture for improving parameter estimation performance, this paper introduces a novel polarization sensitive array composed of augmented and optimallynested subarrays with differently oriented ante...
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To obtain a large aperture for improving parameter estimation performance, this paper introduces a novel polarization sensitive array composed of augmented and optimallynested subarrays with differently oriented antennas, and then proposes an algorithm for direction of arrival (DOA) and Stokes parameter estimation of completely and partially polarized signals, in unknown nonuniform noise environment and without source number knowledge. The aperture of the proposed array significantly increases since the difference co-array of the optimallynested subarray can obtain the maximum degrees of freedom. There is a systematic procedure to determine the numbers of antennas in the two subarrays in order to obtain similar apertures for the two subarrays. Unfortunately, both the difference co-arrays of the optimallynested subarray and between the two subarrays have holes, which degrades performance of parameter estimation. By using oblique projection operators, the proposed algorithm first fills the holes and suppresses the nonuniform noise to obtain hole-free and noiseless difference co-arrays, and then the difference co-arrays are employed to form a block-sparsity model. Finally, based on the model, block orthogonal matching pursuit algorithm is used for parameter estimation. The Cramer-Rao bound and its existence condition are derived. Simulation results are given to demonstrate the superior performance of the proposed array and method. (C) 2020 Elsevier B.V. All rights reserved.
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