Large-Scale Metrology Instrument Performance Evaluations at NIST

Abstract

The ASME B89 committee on dimensional metrology has approved a new U.S. national standard, ASME B89.4.19, “Performance evaluation of laser-based spherical coordinate measurement systems.” This standard, to be published in 2006, specifies test methods for traceable calibrations of laser trackers for the measurement of point-to-point length. NIST has completed a dedicated facility for performing the complete set of B89.4.19 tests. In this article, we describe this facility and its use for testing the range measurement capability and volumetric performance of laser trackers. We also describe the extension of the 60-m laser interferometer range test facility to instruments other than laser trackers and a separate calibrated 65-m linear array of titanium spheres that can be used for testing laser radars, 3-D laser scanners and other large-scale metrology instruments that do not require cooperative targets. turers, national laboratory researchers and interested academics collaborated to write the new B89.4.19 standard. Following is a brief overview of the B89.4.19 test procedures that are described in detail in the standard. We do not include all of the information required to perform the tests. We also describe a dedicated test facility at NIST designed to perform the full range of performance tests called for in the standard, and briefly describe extensions of the test facility to other types of large-scale optical measurement systems.