A universal precision positioning equipment in coordinate unified for large scale metrology

In this article we describe the design of universal precision positioning equipment and the method to be used in the multi stations coordinate unified of large scale measurements. The system incorporates the concept of distance constrains to control the random error of common points. Measuring each point of the artifacts with the coordinate measuring machine which have higher accurate and obtaining the spatial geometry relationships of them. Used the coordinate data of measurements on site in artifacts to obtain the spatial geometry relationships and compared them with the calibrated relationships. Simultaneously can find the large error of the common points and controlled the error in a set range to achieve the traceability of measurement on site. Then use the common points which satisfied the setting range to transform the coordinate to reference. We get a higher precision coordinate unified with the algorithm of 7 parameters Procrustes. The present method is used in coordinate unified for electronic theodolites and laser tracker. The results show that the accuracy using the artifact is much better than traditional method.