Laser Tracker Testing at NIST in Accordance with the ASME B89.4.19 Standard

Abstract

While the versatility and economics of laser trackers are quite appealing, the ability to assess their accuracy and to compare various brands has been limited by the lack of a national or international standard that encompasses testing and traceability procedures. This situation has now changed. In 2006, the American Society for Mechanical Engineers Board on Standardization and Testing approved the new B89.4.19 standard—“Performance Evaluation of LaserBased Spherical Coordinate Measurement Systems,” which appeared in print in January 2007. This standard provides manufacturers and users with a common and well-defined set of tests that can be performed to evaluate laser trackers and other spherical coordinate measurement systems that use cooperative targets. In this paper, we provide a brief overview of the B89.4.19 tests, describe our large-scale facilities at the National Institute of Standards and Technology, and discuss some experimental results of B89.4.19 tests performed on commercial trackers. Based Spherical Coordinate Measurement Systems,”1 which is now in print and available through the ASME Web site at www .asme.org. The B89.4.19 standard describes performance tests for trackers that use a cooperative target such as a retroreflector. Typical IFM and ADM trackers therefore fall under the purview of this standard. Laser scanners that function with noncooperative targets are not currently covered by the standard, however, some of these systems can use a tooling ball as a