Path tracking with IGPS

iGPS technology is a laser-based indoor system with optical sensors and transmitters to determine the 3D/4D 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 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 the time-referenced 4D test and calibration system (Ti4Calibs). By using the latest equipment and Surveyor software it was possible to show that the iGPS system has made significant improvement in tracking capability. 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 at this high velocity the tracking deviations for the 3D position were less than 0.3 mm and the 4D tracking deviations were less than 1.5 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.