Rotating swivel unit for sensors of a coordinate measuring apparatus and method for determining corrective parameters of the rotating swivel unit

A rotating swivel unit for a sensor of coordinate measuring apparatus, the sensor measuring in at least one dimension and the rotating swivel unit comprising:

• at least two swivel joints for aligning the sensor with respect to angle;
• a corrective unit for correcting the measured values of the sensor, when measuring, in correspondence to the rotational position of said swivel joints;
• means for picking up corrective values which include functioning to:
• carry out a calibration of said sensor for at least three rotational positions of one of said swivel joints with said sensor measuring in at least one dimension;
• compute at least parameters of a first parameter field (MS) for each of said rotational positions with said first parameter field (MS) describing the transformation of a sensor coordinate system (u,v,w) into a machine coordinate system (XM, YM, ZM) of the coordinate measuring apparatus;
• compute parameters of a second parameter field (ps) describing an offset of said sensor coordinate system (u,v,w) with respect to a point (AB) in said machine coordinate system (XM, YM, ZM);
• and,
• determine corrective parameters of said swivel joint from said parameters of said first and second parameter fields.