SAMV (iterative sparse asymptotic minimum variance) is a parameter-free superresolution algorithm for the linear inverse problem in spectral estimation, direction-of-arrival (DOA) estimation and tomographic reconstruction with applications in signal processing, medical imaging and remote sensing. The name was coined in 2013 to emphasize its basis on the asymptotically minimum variance (AMV) criterion. It is a powerful tool for the recovery of both the amplitude and frequency characteristics of multiple highly correlated sources in challenging environments (e.g., limited number of snapshots and low signal-to-noise ratio). Applications include synthetic-aperture radar, computed tomography scan, and magnetic resonance imaging (MRI).
Definition The formulation of the SAMV algorithm is given as an inverse problem in the context of DOA estimation. Suppose an M {\displaystyle M} -element uniform linear array (ULA) receives K {\displaystyle K} narrow band signals emitted from sources located at locations θ = { θ a , … , θ K } {\displaystyle \mathbf {\theta } =\{\theta _{a},\ldots ,\theta _{K}\}} , respectively. The sensors in the ULA accumulates N {\displaystyle N} snapshots over a specific time. The M × 1 {\displaystyle M\times 1} dimensional snapshot vectors are
y ( n ) = A x ( n ) + e ( n ) , n = 1 , … , N {\displaystyle \mathbf {y} (n)=\mathbf {A} \mathbf {x} (n)+\mathbf {e} (n),n=1,\ldots ,N}
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