Abstract:A simple ISAR range-Doppler algorithm is applicable to steadily small flying target. But for maneuvering target the assumption is not satisfied, as the Doppler frequency is time variant. Actually to obtain the cross-range resolution of dozens of centimeters for the large-scale or medium targets especial for S or L wave band, whose wave length is not short, the Migration Through Resolution Cell (MTRC) would be occurred on the both fringe of the ISAR imaging. In this paper the reason that caused migration through resolution cell is discussed, and a compensating algorithm is proposed. Simulation data and real data prove that this method is effective.