Subarray selection in octave arrays

Kaderoğlu, Ali Rıza
Sensor layout of the octave array is designed to process a frequency range of several octaves. Array aperture of the highest octave band is limited to uniform line array (ULA) segment at the center. Forming a sparse array layout for the highest frequency band by using some of the remaining elements apart from ULA could bring some advantages such as higher array gain and better detection performance. Using a sparse array has a drawback of violating the spatial Nyquist limit, which may cause high sidelobes to appear in the beampattern. It is aimed to select an optimum layout with larger aperture length and higher gain without being affected by disadvantages of using sparse arrays. Performance of the selected layout depends on the used direction of arrival estimation (DOA) method. In this thesis, both conventional and coarray based DOA methods are reviewed firstly. Then, several optimization problems are stated for selecting a subarray layout. These problems use some array parameters such as peak-to-sidelobe level (PSL), Cramer-Rao bound, method of interval errors (MIE) and redundancy. Minimization of PSL is used to reduce the high sidelobe levels. To minimize DOA estimation error, CRB and MIE are used as cost functions. PSL constraint is added to minimization of CRB problem to prevent grating lobes in the array beampattern. Minimum redundancy array and robust minimum redundancy array are obtained by using redundancy and fragility in the optimization problems. Performances of proposed array layouts are compared with the existing solution using extensive computer simulations.


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Citation Formats
A. R. Kaderoğlu, “Subarray selection in octave arrays,” M.S. - Master of Science, Middle East Technical University, 2022.