Fig. 1. Measurement system for four degrees of freedom heterodyne interference.

Fig. 2. Change of light path in straightness sensor caused by straight line migration

Fig. 3. Schematic diagram of a four-quadrant detector for differential wavefront sensing with tilt measurement wavefront.

Fig. 4. Top view of light path passing through wedge prism and wedge mirror

Fig. 5. Optical path change caused by wedge-angle prism deflection

Fig. 6. Optical path changes in wedge-shaped prisms caused by elevation angle

Fig. 7. Optical path changes in wedge prisms caused by roll angle