Fig. 1. Principle of GM-APD laser ranging

Fig. 2. Timing diagram of the ranging system

Fig. 3. Generation principle of equivalent high frequency counting clock

Fig. 4. Principle of two-stage TDC time quantization

Fig. 5. TDC timing of coarse and fine two stages

Fig. 6. Generation principle of equivalent high frequency counting clock

Fig. 7. Internal counter unit structure of TDC

Fig. 8. Work flow of laser ranging system

Fig. 9. RTL structure diagram of frequency division module

Fig. 10. RTL structure of fine time digital conversion circuit

Fig. 11. Timing results of TDC

Fig. 12. Timing results of TDC

Fig. 13. Laboratory experiment scene

Fig. 14. (a) 1457 m residential building; (b) Ranging results of the rangefinder

Fig. 15. (a) 2616.5 m residential building; (b) Ranging results of the rangefinder

Fig. 16. Ranging results at 1457 m

Fig. 17. Ranging results at 2616.5 m