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On the estimation of grid offsets in CS-based direction-of-arrival estimation

: Ibrahim, Mohamed


Institute of Electrical and Electronics Engineers -IEEE-; IEEE Signal Processing Society:
IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP 2014. Vol.9 : Florence, Italy, 4 - 9 May 2014
Piscataway, NJ: IEEE, 2014
ISBN: 978-1-4799-2894-1
ISBN: 978-1-4799-2892-7
ISBN: 978-1-4799-2893-4
International Conference on Acoustics, Speech and Signal Processing (ICASSP) <39, 2014, Florence>
Fraunhofer IIS ()
Richtungsschätzung (DoA); compressed sensing

Compressed Sensing (CS) has been recently applied to direction of arrival (DOA) estimation, leveraging the fact that a superposition of planar wavefronts corresponds to a sparse angular power spectrum. However, to apply the CS framework we need to construct a finite dictionary by sampling the angular domain with a predefined sampling grid. Therefore, the target locations are almost surely not located exactly on a subset of these grid points. This leads to a model mismatch which deteriorates the performance of the estimators. In this paper we take an analytical approach to investigate the effect of such grid offsets on the recovered spectra. We show that each off-grid source can be well approximated by the closest two neighboring points on the grid. We propose a simple and efficient scheme to estimate the grid offset for a single source or multiple well-separated sources. We also discuss a numerical procedure for the joint estimation of the grid offsets of closer sources. Simulation results demonstrate the effectiveness of the proposed methods.