Fig. 1. Double-pulse waveform

Fig. 2. Principle of double-pulse velocimetry and ranging

Fig. 3. Construction principle of a double pulse coherent system

Fig. 4. Relationship between target micro-motion frequency and phase difference

Fig. 5. Relationship between pulse interval and double-pulse phase difference of double-pulse system detecting low- and high-speed targets. (a)‒(c) Low-speed target; (d)‒(f) high-speed target

Fig. 6. Relationship between pulse interval and double-pulse phase difference of double-pulse system detecting ultrahigh-speed targets. (a)Ultrahigh-speed target with frequency of 500 Hz; (b) ultrahigh-speed target with frequency of 1 kHz

Fig. 7. Relationship between pulse interval and double-pulse phase difference of double-pulse system detecting ultrahigh-speed targets. (a)Ultrahigh-speed target with frequency of 5 kHz; (b) ultrahigh-speed target with frequency of 10 kHz; (c) ultrahigh-speed target with frequency of 1 MHz

Fig. 8. Effect of CNR on shooting noise

Fig. 9. Effect of ΔT/T_s on coherent noise

Fig. 10. Experimental schematic diagram

Fig. 11. Experimental setup photos. (a) Photo of the loop; (b) NKT laser; (c) the target and revolving stage

Fig. 12. Generated double-pulse signal

Fig. 13. Comparison of double-pulse signals measured by the two balanced detectors

Fig. 14. Double-pulse signal measured by balanced detector 2

Fig. 15. Parameters such as loop-length of detected target and pulse interval of double-pulse show dependence with LIDAR parameters