iGPS Used as Kinematic Measuring System

SUMMARY iGPS is a measurement system which uses laser transmitters and sensors to determine the 3D position of static or moving objects. The technology is based on internal time measurements related to spatial rays that intersect at sensors in the measuring volume. The advantage of the iGPS system is the flexibility by using multiple transmitters and sensors. In this way the measurement volume can be configured to the size of the application, which can be scaled from small work cells to facility-wide installations. The typical applications are found in industrial manufactures, primarily in aerospace, automotive and shipbuilding industries. The static iGPS accuracy is well known, but there is a lack of testing the tracking accuracy with the latest system developments. Due to the measurement principle of iGPS, tracking measurements can caused a delay time which will lead to deviations in spatiotemporal positioning. Utilizing the new Digital Input Module it is possible to examine the iGPS system with a time-referenced 4D test and calibration system. In this paper measuring result examples are represented in order to show the iGPS performance under kinematic conditions (time and space). Velocities up to 3 m/s were reached and the 4D tracking deviations were less than 1.5 mm. At velocities lower than 1 m/s the 4D deviations decrease to below 0.5 mm. These results show that Nikon has reached to reduce the theoretical delay time and that iGPS is not only a static metrology system but also capable for tracking applications.