Articles: Department of Mathematics and Statistics

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Browsing Articles: Department of Mathematics and Statistics by Subject "Array signal processing"

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    Aperture Maximization with Half-Wavelength Spacing, via a 2-Circle Concentric Array Geometry that is Uniform but Sparse
    (Journal of Advances in Mathematics and Computer Science, 2019-05-25) Kinyili, Musyoka; Kitavi, Dominic Makaa; Ngari, Cyrus Gitonga
    This paper proposes a new sensor-array geometry (the 2-circle concentric array geometry), that maximizes the array’s spatial aperture mainly for bivariate azimuth-polar resolution of direction-of-arrival estimation problem. The proposed geometry provides almost invariant azimuth angle coverage and offers the advantage of full rotational symmetry (circular invariance) while maintaining an inter-sensor spacing of only an half wavelength (for non-ambiguity with respect to the Cartesian direction cosines). A better-accurate performance in direction finding of the proposed array grid over a single ring array geometry termed as uniform circular array (UCA) is hereby analytically verified via Cram´er-Rao bound analysis. Further, the authors demonstrate that the proposed sensor-array geometry has better estimation accuracy than a single ring array.
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    Cramer-Rao Bound of Direction Finding Using Uniform Arc Arrays
    (2019) Nyokabi, Veronicah; Kitavi, Dominic M.; Ngari, Cyrus G.
    Direction-of-Arrival estimation accuracy using arc array geometry is considered in this paper. There is a scanty use of Uniform Arc Array (UAA) in conjunction with Cram er-Rao bound (CRB) for Direction-of-Arrival estimation. This paper proposed to use Uniform Arc Array formed from a considered Uniform Circular Array (UCA) in conjunction with CRB for Direction-of-Arrival estimation. This Uniform Arc Array is obtained by squeezing all sensors on the Uniform Circular Array circumference uniformly onto the Arc Array. Cram er-Rao bounds for the Uniform Arc Array and that of the Uniform Circular Array are derived. Comparison of performance of the Uniform Circular Array and Uniform Arc Array is done. It was observed that Uniform Arc Array has better estimation accuracy as compared to Uniform Circular Array when number of sensors equals four and ve and azimuth angle ranging between π 9 7 and π and also 18 10 9 π and 25 18π. However, UCA and UAA have equal performance when the number of sensors equals three and the azimuth angle ranging between 0 and 2π. UCA has better estimation accuracy as compared to UAA when the number of sensors equals four and ve and the azimuth angle ranging between π 2 and π and also 32 π and 2π