Fig. 1. Geometry of radar observing a moving target

Fig. 2. Schematic diagram of Sequential ISAR imaging

Fig. 3. Schematic diagram of LFM signal in time domain and fractional Fourier domain

Fig. 4. Flow chart of the proposed algorithm.

Fig. 5. Experimental radar system in the scene and the imaged truck

Fig. 6. ISAR images of Frame 11

Fig. 7. ISAR images of Frame 12

Fig. 8. ISAR images of Frames7~12（The top row： FrFT， the middle row： PGA. the bottom row： the proposed algorithm）

Fig. 9. Sequence of estimated ACRs in real radar data experiment