This paper details a method of determining the uncertainty of dimensional measurement for a three dimensional coordinate measurement machine. An experimental procedure was developed to compare three dimensional coordinate measurements with calibrated reference points. The reference standard used to calibrate these reference points was a fringe counting interferometer with the multilateration technique employed to establish three dimensional coordinates. This is an extension of the established technique of comparing measured lengths with calibrated lengths. Specifically a distributed coordinate measurement device was tested which consisted of a network of Rotary-Laser Automatic Theodolites (R-LATs), this system is known commercially as indoor GPS (iGPS). The method was found to be practical and able to establish that the expanded uncertainty of the basic iGPS system was approximately 1 mm at a 95% confidence level.
J E Muelaner, Z Wang, J Jamshidi, P G Maropoulos
Department of Mechanical Engineering, The University of Bath, Bath, UK
6th International Conference on Digital Enterprise Technology. 2009: Hong Kong
*Best Paper Award
**Results given in this paper were obtained using the original Workspace software
and a typical 4 transmitter setup. Further testing has shown that uncertainty may
be reduced by using newer software versions, and more complicated configurations
with more hardware.
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