ON THE USE OF OPTICAL FIBERS IN A PULSED TIME-OF-FLIGHT LASER RANGEFINDER

The pulsed time-of-flight laser rangefinding technique has been used i n many industrial measurement applications, including 3D-coordinate me asuring devices, hot surface profilers and mobile robot sensors. Optic al fibres, typically 1-10 m in length and 100-400 mum in diameter can be used to guide optical pulses to the separate sensing head of the me asurement device. The use of a large multimode fibre may cause problem s, however, when aiming at millimetre accuracy, as the construction an d adjustment of the optics of the sensor head may affect the transit t ime linearity and measurement accuracy via multimode dispersion. Envir onmental effects, such as bending, vibration due to the moving sensing head and temperature, also cause measurement errors. The error source s are studied and characterized in this paper.