relative to the measuring standards the position of the table is determinable by the scanning heads in six degrees of freedom in at least one of the corners one or more scanning heads having a total of at least three measuring axes is are provided for 3 d position detection in three independent spatial directions sensitivity vectors of the measuring axes for the 3 d position detection are neither parallel to the x z plane nor parallel to the y z plane application_number US 201414508553 A description before exemplary embodiments of the optical position measuring device are described below the position measuring device described in european published patent application no 1 762 828 and in u s pat no 7 573 581 each of which is expressly incorporated herein in its entirety by reference thereto is briefly explained as mentioned above it is suitable for detecting position changes along two shift directions in the corresponding scanning head two scanning beam paths are formed so as to be tilted or asymmetrical relative to each other in this connection the beam of rays delivered by a light source is supplied via a first optical fiber in the form of a single mode fiber to the scanning system and after being coupled out of the optical fiber is collimated via collimating optics the collimated beam of rays thereupon arrives at a splitting grating in which it is split into two scanning beam.