A fast alternating projection method for complex frequency estimation
  The problem of approximating a sampled function using sums of a fixed number of complex exponentials is considered. We use alternating projections between fixed rank matrices and Hankel matrices to obtain such an approximation. Convergence, convergence rates and error estimates for this technique are proven, and fast algorithms are developed. We compare the numerical results obtain with the MUSIC and ESPRIT methods. 
Fredrik Andersson, Marcus Carlsson and Per-Anders Ivert
math.NA