Common-Path Method for Laser Tracker Ranging Calibration
Christopher J. Blackburn, Daniel S. Sawyer, Craig M. Shakarji
We present an alternative to the back-to-back method of testing laser tracker ranging systems. Our approach uses a common air path for both the measurement and reference laser beams. This technique allows for more accurate determination of the reference length by greatly reducing the dead-path for the reference length. Accuracy is also improved because of the use of a single optic: this eliminates error sources due to offsets between the front- and rear-facing optics used in the back-to-back method. Furthermore, the technique simplifies the execution of the ranging test by allowing for a novel alignment procedure that is also presented.