3-DOF angle measurement method based on two interference images

With the development of observation satellite, precision lathe and lithography, the demand for high-precision three-degree of freedom (3-DOF) angle measurement instruments is becoming increasingly urgent. Laser measurement has the advantages of high accuracy, non-contact, and large measurement range and is widely used in this area. We established a 3-DOF angle measurement method using two lasers and set a new algorithm to decouple its mathematical model. We analyzed the factors that may affect the resolution of this method, and achieved the simultaneous measurement of pitch, yaw, and roll angles in theory. Our method has high resolution theoretically and does not have the problem of inconsistent coordinate references.