Calibration method of extrinsic parameters for non-orthogonal shaft laser theodolite measurement system

Abstract

Non-orthogonal shaft laser theodolite(N-theodolite) measurement system is a new kind of measurement instrument utilized in large-scale metrology, which is made up of two same N-theodolites. To achieve the transformation of N-theodolites’ coordinate systems, a calibration method of extrinsic parameters is proposed. With the help of a scale-bar of a certain length, the calibration can be performed conveniently. The correctness of the calibration method is verified by the measurement experiments of point coordinates and distances. The experimental results show that the RMSE of spatial points and the distances of measured points are 0.319mm and 0.150mm respectively. We demonstrate that the proposed calibration method of extrinsic parameters is feasible for the N-theodolite measurement system.