Absolute distance meter based on a frequency-modulated laser diode

This article describes a distance measuring instrument based on a frequency-modulation continuous wave interferometer implemented in a compact setup suitable for industrial applications. The prototype uses a visible laser diode that is frequency-modulated with a triangular wave form. Measurements carried out with a cooperative target show a measuring range from 130 to 300 mm with a relative accuracy of 1.2 X 10(-3). (C) 1998 American Institute of Physics.