Abstract:A practical modified autofocus algorithm for synthetic aperture radar, the iterative shift-and-correlation algorithm, is presented, Comparing with the original shift-and-correlation algorithm, the modified one can obtain more accurate estimations in worse case by incorporating the appropriate iterations, the new weightings and the auto-selecting width of the detecting window. Both the theoretical analyses and the test results indicate that the iterative shift-and-correlation algorithm can obtain more reliable results with a cost of slight increment of the computational complexity.