Fig. 1. Structural diagram of fine tracking system

Fig. 2. Control principle block diagram of fine tracking subsystem

Fig. 3. Experimental system

Fig. 4. Disturbing signal. (a) Disturbing signal generated by signal generator; (b) probability density of disturbing signal

Fig. 5. Deviation between spot centroid and tracking point. (a) 12 bit digital to analog converter; (b) 14 bit digital to analog converter; (c) 16 bit digital to analog converter

Fig. 6. Deviation between disturbed spot centroid and tracking point. (a) 12 bit digital to analog converter; (b) 14 bit digital to analog converter; (c) 16 bit digital to analog converter

Fig. 7. Tracking accuracy under different window sizes