Performance evaluation of laser trackers

The American Society for Mechanical Engineers (ASME) recently released the ASME B89.4.19 Standard [1] on performance evaluation of spherical coordinate instruments such as laser trackers. At the National Institute of Standards and Technology (NIST), we can perform the complete set of tests described in the Standard, and have done so for a variety of laser trackers. We outline the tests described in the Standard, discuss our capabilities at the large-scale coordinate metrology group, and present results from B89.4.19 tests conducted on a few trackers. We also outline an analysis approach that may be used to evaluate the sensitivity of any measurement, including the tests described in the B89.4.19 Standard, to different geometric misalignments in trackers. We discuss how this approach may be useful in determining optimal placement of reference lengths to be most sensitive to different geometric misalignments.