Fig. 1. Schematic diagram of free space laser quantum communication

Fig. 2. Light-weighting gimbal terminal

Fig. 3. Schematic diagram of composite axis precision tracking system

Fig. 4. Schematic model of 1^st and 2^nd modal diagram of the light-weighting gimbal terminal

Fig. 5. Block diagram of control model for composite axis precision tracking system

Fig. 6. Schematic diagram of structural and driving model of fast steering mirror

Fig. 7. Schematic diagram of fine precision tracking closed loop control system

Fig. 8. Schematic diagram of intelligence tuning PID digital control algorithm

Fig. 9. Open Bode plot of fine precision tracking sub system

Fig. 10. Closed loop Bode diagram of fine precision tracking sub system

Fig. 11. Tracking trajectory of gimbal coarse tracking sub system

Fig. 12. Closed loop control accuracy of gimbal coarse tracking sub system

Fig. 13. Frequency characteristics of gimbal coarse tracking sub system

Fig. 14. Static closed loop control accuracy of fine precision tracking sub system

Fig. 15. Dynamic closed loop control accuracy of fine precision tracking sub system

Fig. 16. Low-frequency disturbance suppression effect of composite axis fine tracking system