Robot calibration is a process to improve the robot accuracy by software modifications without changing the mechanical structure or design of the robot. This paper presents a comparison of three similar robot calibration procedure. The kinematic model used in all of three methods is the one derived from the Rodrigue's formula. In the model, robot geometry is represented by kinematic parameters. Each calibration procedure utilizes a specific measuring device to collect robot pose data from which the actual kinematic parameters can be identified. In addition to describing the hardware this paper also includes the calibration results based on the experimental data.