In the stepped-frequency radar system

motion introduces additive high order phase terms

which results in distortion of range profile.The phase modulation effect is analyzed and a novel ISAR imaging method is proposed for uniformly accelerative target

which based on predesigned waveform and phase cancellation.The pulse repetition time is predesigned to eliminate the high order phase terms introduced by velocity of the target.Then the high order phase terms introduced by acceleration are removed by phase cancellation.For a uniformly accelerative target

the velocity and acceleration are not need to estimate in the proposed method

so the computation burden is greatly reduced.Simulations with synthetic data demonstrate the performance of the new method.The results confirm its effectiveness.