Nested sensor array extension factors required to match the peak sidelobe height of a uniform linear array

Abstract

Nested sensor arrays (NSAs) are a type of non-uniform linear array (NULA) that reduce the total number of sensors used for a given aperture and retain the same resolution of a uniform linear array (ULA) [Pal and Vaidyanathan, 2010]. The peak sidelobe (PSL) height fails to fall below the acceptable standard of -13 dB associated with ULAs for basic NSA configurations. The basic NSA can be extended by a factor to improve the PSL height. Coprime sensor arrays, a related NULA design, have established sensor extension factors that have been found to reduce the PSL height to this -13 dB standard [Adhikari et al., 2014]. For NSAs, such an extension factor has not been established. This research finds the parameters required to extend an NSA to adequately reduce the PSLs. NSAs can significantly reduce the number of sensors required to yield a satisfactory beampattern, as low as twenty-five percent of the total aperture for some cases. Considering various array apertures, certain configurations successfully use a distinctly small aperture but require a higher percentage of those to be active. To verify our results, we construct a sixty-four sensor microphone array with which we test the optimal configurations. [Work supported by Louisiana Tech University.]