Development of a high-accuracy multi-sensor, multi-target coordinate metrology system using frequency scanning interferometry and multilateration

We present a novel coordinate measurement system based on a combination of frequency scanning interferometry and multilateration. The system comprises a number of sensors (minimum of four) that surround the measurement volume. Spherical glass retro-reflectors act as targets that are used to define the points in space to be measured. The sensors all measure the absolute distance to all targets simultaneously. The resulting distances are then used to compute the coordinates of the targets and other systematic parameters such as the sensor locations. Initial experimental comparison with a commercial laser tracker has shown that the proposed system is capable of achieving coordinate uncertainties of the order of 40 mu m in a measurement volume of 10 m x 5 m x 2.5 m. The system is self-calibrating, inherently traceable to the international system of units (the SI) and computes rigorous coordinate uncertainty estimates.