Fig. 1. The BIDWIN optical system structure layout^[13]

Fig. 2. The simulated four-zone interferogram of BIDWIN

Fig. 3. The stepped phase changes with the field of view

Fig. 4. sin(Q) changes with the field of view

Fig. 5. Wind speed measurement errors

Fig. 6. The second delay plate is rotated 2° around the z-axis. (a) Simulated four interferogram; (b) Phase step difference between upper and lower zones; (c) Value of sin(Q); (d) Simulated wind speed measurement error

Fig. 7. The second delay plate is rotated 5° around the z-axis; (a) Simulated four interferogram; (b) Phase step difference between upper and lower zones; (c) Value of sin(Q); (d) Simulated wind speed measurement error

Fig. 8. The changes in the number of strips of maximum wind speed measurement error and the remaining available field of view with the rotation angle of the second delay plate around the z-axis

Fig. 9. The second delay plate is rotated 0.5° around the y-axis. (a) Simulated four interferogram; (b) Phase step difference between upper and lower zones; (c) Value of sin(Q); (d) Simulated wind speed measurement error

Fig. 10. The second delay plate is rotated 5° around the y-axis. (a) Simulated four interferogram; (b) Phase step difference between upper and lower zones; (c) Value of sin(Q); (d) Simulated wind speed measurement error

Fig. 11. The changes in the displacement of the center point of the available field of view with the rotation angle of the second delay plate around the y-axis (The downward displacement is positive)

Fig. 12. The whole system is rotated 2° around the y-axis. (a) Simulated four interferogram; (b) Phase step difference between upper and lower zones; (c) Value of sin(Q); (d) Simulated wind speed measurement error