Dynamic Weighting of Laser Tracker Measurements for Bundle Adjustment

A laser tracking interferometer system provides real-time three-dimensional measurements in large volumes. It is portable and easily moved to the measurement site. Laser trackers are spherical measurement systems that measure a three-dimensional location of a retro-reflector. The bundle adjustment is a method that computes coordinates from laser tracker measurements. It maximizes the accuracy by allowing each individual measurement to be weighted based upon their type and accuracy. This study will define the bundle adjustment angle and range measurement uncertainty dependence relative to the distance between the Laser Tracker and the retro-reflector. The study shows that by weighting the range and angle data with appropriate functions, the residuals of the measurements are smaller and thus the uncertainty of point coordinate data is improved. The study presents test data collected in control laboratory environment, then confirms the improvements by comparing bundle adjustment results of real data with and without the modified weighting approach.