Development Of Novel Approaches For High Resolution Direction Of Arrival Estimation Techniques

  • Ramaswamy K. Balasubramanian

Student thesis: Doctoral ThesisDoctor of Philosophy


This thesis presents the development of MUSIC algorithm based novel approaches for the estimation of Direction of Arrival (DOA) of electromagnetic sources. For the 2D-DOA estimation, this thesis proposes orthogonally polarized linear array configuration rather than the conventionally invoked two dimensional array. An elegant one dimensional search technique to compute 2D-DOA estimation for a single source scenario has been proposed. To facilitate one dimensional search for 2D-DOA estimation, a closed form relationship between the azimuth and elevation angles
of the 2D-DOA is derived using the analytical expressions of radiation patterns of Rectangular Waveguide (RWG) and Circular Waveguide (CWG). The computation time for the proposed one
dimensional search technique is reduced by a factor of 50 and 150 for 1 and 0.5 search interval respectively. To improve the accuracy and the resolution of 2D-DOA estimation in case of closely
spaced sources, this thesis proposes novel array configurations such as orthogonally polarized planar array, orthogonally mounted linear array and orthogonally polarized linear array. Through
numerous simulation studies, a relative performance comparison of 2D-DOA estimation realized through various proposed novel array configurations has been carried out to highlight the accuracy and resolution under wide range of SNR conditions. The thesis presents a discussion on the analysis of effect of spatial de correlation in lieu of the employed orthogonally polarized elements in the array configuration on the improved accuracy and resolution of the 2D-DOA estimation.

This thesis also deals with the utility of the proposed orthogonally polarized array configurations for tracking of 2D-DOA angles of non-stationary signal sources. The weighting factor and forgetting factor approaches for smoothing the time-varying covariance matrix of the non-stationary sources are studied. The simulation studies on 2D-DOA tracking by invoking proposed array
configurations along with the proposed smoothing techniques prove that orthogonal polarized array configuration track the DOA source angle with minimum estimation errors. The thesis proposes
the replacement of computationally intensive numerical schemes in Multiple Signal Classification (MUSIC) algorithm such as eigen decomposition and singular value decomposition with the sub-space tracking techniques such as Bi-Iterative Singular Value Decomposition (Bi-SVD) algorithm. Invoking the concept of sub-band processing, the thesis addresses the validity of the extension of the presented 2D-DOA estimation analysis to wide band signal. A two subband filter approach is proposed for the estimation 2D-DOA of single and two wideband sources. The simulation study of
the two subband filter approach along with the orthogonal polarized array configurations confirms the better estimation accuracy as well as the lesser computation time.
Date of Award2016
Original languageEnglish
Awarding Institution
  • Coventry University
SupervisorGovind Kadambi (Supervisor), M. S. Ramaiah (Supervisor) & Yuri Vershinin (Supervisor)

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