1999, 21(6): 771-778.
Abstract:
This paper presents an improved rank one phase error estimation(ROPE) autofo-cusing technique. Compared with ROPE, the improved algorithm has two distinct advantages: first, its model is more actual, so its property of robustness is better; second, at the begining of its iteration process, the initialized valves are set up approximately. Through approximate analysis, this paper proves that the improved algorithm s estimation of phase error is maximum-likelihood (ML), and, under some special situaitons, its estimation is the same as that of phase gradient autofocus (PGA), which is linear unbiased minimum variance (LUMV) estimation. PGA is a subset of this improved autofocus algorithm. Finally, some simulation results are given.