Application of bundle adjustment to accuracy evaluation of laser tracker

The accuracy evaluation methods for a laser tracker developed by ourselves are investigated to solve the problem that the coordinate precision in a large-size space coordinate measuring system is difficult to be evaluated.In consideration of the great impacts of environmental conditions,equipment status,operator skills and other factors on measurement accuracy,this paper proposes a bundle adjustment method to evaluate the accuracy of the laser tracker under practical conditions.The Matlab is used to simulate the accuracy evaluation,and results show that the bundle adjustment can generally reflect the measurement accuracy of laser tracker measurement system.Furthermore,a practical experiment is performed on a laser tracker made from Faro company,and results show that the measuring accuracies of horizontal angle σ_H and vertical angle σ_V are 1.97″ and 2.61″,respectively,and measuring accuracy σ_D for the distance is 3.75×10-6.As compared with the instrument accuracy of the Faro(σ_H=2.0″,σ_V=2.0″,σ_D=4 μm),It proves that using bundle adjustment to evaluate the performance of the laser tracker developed is feasibility and correctness.The method will be useful to broaden application of laser tracker technology and to open a way to task-oriented uncertainty evaluation.