Patent attributes
A device capable of measuring one or more degrees of freedom with respect to a beam of light is described. The angle of rotation around the beam is obtained with a polarized beam of light and a polarizing optic and a sensor. A control system holds a sensor reading to a predetermined value. Therefore as the device is rotated around the beam, the optic will be rotated to maintain the sensor reading and an encoder provides the measurement of the amount of rotation. A position sensing device provides transverse information about the location of the beam and rotation of the device around two other axes. A second position sensing device at a difference distance from the light transmitter allows for the separation of transverse and rotational measurements. Alternately, the transverse measurement can be obtained by a light transmitter capable of making the measurement on a reflected beam.
