Fig. 1. Block diagram of four-quadrant detector coherent detection system

Fig. 2. Relation curve between system SNR and local oscillator power

Fig. 3. Spot position distribution of four-quadrant detector. (a) At center of photosensitive surface; (b) deviating from center of photosensitive surface

Fig. 4. Overall block diagram of simulation system algorithm model

Fig. 5. Error evaluation process. (a) Error in x axis; (b) error in y axis

Fig. 6. Influence of beat signal noise on position detection accuracy. (a) Incoherent; (b) coherent

Fig. 7. Influence of detector noise on position detection accuracy. (a) Incoherent; (b) coherent

Fig. 8. Influence of Gaussian spot radius on position detection accuracy. (a) Incoherent; (b) coherent

Fig. 9. I Influence of spot center position on position detection accuracy. (a) Incoherent; (b) coherent